Characterization of advanced materialsZU
Advanced composite materials: production, testing, applications
Introduction and scope:
It is difficult to imagine our life without various kinds of advanced ceramic and composite materials because of new unique properties of such kind of materials from one side and appearing the new areas of their application from another side. For traditional application areas of advanced engineering and functional ceramic and composites and complex structures on their base (such as aeronautic, space, transport, energy, micro- and nanoelectronics ) it is necessary to create the new materials and multicomponent structures with given complex of service properties, based on existing knowledge and modern methods of modeling. For relatively new areas of advanced functional ceramic and composite applications which are highly developed in last years (materials for biomedicine and ecology, renewable energy sources) it is necessary to create absolutely new kinds of ceramic materials and complex structures with unique service parameters. All these problems will be in the focus of our symposium activity in 2016.
Traditional ceramic materials which compared to metals and plastics are hard, non-combustible and inert are widely used for high temperature, corrosive and tribological applications. So because of unique combination of such properties of advanced ceramic as retention of properties at high temperature, low coefficient of friction (particularly at high loads and low levels of lubrication),
low coefficient of expansion, thermal and electrical insulation parameters, low density it became possible to create a new materials on the base of oxide, nonoxide and functional ceramic and corresponding types of composites. Last years the new possibilities of applications for complex structures with special ceramic coatings had been revealed, including new kinds of space, aeronautic and automobile materials, biomaterials, materials for military applications, biomedical implants and drag delivery, complex fuel cells and renewable energy materials and etc. Development of various kinds of composites allowed combining the attractive characteristics of ceramics with sufficient enhancing of fracture toughness, ductility and tensile strength. Only on the base of advanced ceramic and composite materials (natural, for example, metal eutectic and synthetic such as reinforced heterogeneous inorganic and organic materials) and special structures it became possible to produce high temperature and high-strength details and constructions with high thermal and electrical conductivity, unique magnetic and tribotechnical properties. For advanced ceramics and composites which traditionally used in aeronautic, energy sector, automobile, space and transport industry the task of creating of materials with given complex of service parameters ensuring their safety and reliability became more and more actual. The same situation with various kinds of ceramic and composites for micro and nanoelectronics, new demands to the sizes of electronic devices and widening of their functionalities ensure the necessity of creating of new materials and complex structures with new complex of service characteristics and for these purposes special attention should be paid to the methods of joining of ceramics with other kinds of materials. Modern methods of modeling for advanced ceramics, composites and complex structures production, micro-and macrostructure and forecasting of the physical and chemical properties allow successfully decide such kind of tasks. Special time will be devoted to innovative research, to the questions of technology transfer and international cooperation in the field of advanced ceramic and composite materials.
Hot topics to be covered by the symposium:
- Fundamental study, modelling of technology processes, structure and properties,including phase equilibria diagramms for multicomponent systems
- Production technologies for advanced ceramic and composites powders and their properties, including the influence of additing of such kind powders on service properties of final product
- Production technologies for ceramic and composites coatings and their properties
- Production technologies for bulk ceramic and composites and their properties, including novel sintering technologies for complex compounds and structures
- Complex ceramic and composite structures for extreme environments
- Nanoceramic and nanocomposites: peculiarities of their structure and properties
- Novel techniques for advanced ceramic and composite materials characterization
- Novel areas of application of advanced ceramic and composites, including space, transport, biomaterials, micro- and nanoelectronic, constructional ones
Results and perspectives of international cooperation in the field of creation of advanced ceramic and composite materials
Tentative list of invited speakers:
- Turkevich Vladimir (Kiev, Ukraine)
- Konstantinova Tatiana (Donetsk, Ukraine)
- Tedenac Jean-Claude (Montpellier, France)
- Sanin Anatolii (Dniepropetrovsk, Ukraine)
- Prikhna Tatiana (Kiev, Ukraine)
- Fragge Nahum (Bersheva, Israel)
- KervalishviliPaata (Tbilisi, Georgia)
- Gogotsi Yu. (Drexel University, USA)
- Shemet V (Jülich, Germany)
|Start at||Subject View All||Num.||Add|
Refractory composites and coatings on the base of them : Dr. IRYNA BILAN
Authors : Christian Huber, Benedikt Stein, Michael Stumber, Heinz Kalt
Affiliations : Microsystem Technologies Department, Corporate Research, Robert Bosch GmbH, 71272 Renningen, Germany; Institute of Applied Physics, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
Resume : Silicon carbonitride (SiCN) deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) has emerged as a promising new material for applications such as wear- and etch-resistant optical antireflection coatings due to its mechanical hardness, low refractive index and chemical inertness. While the ternary composition allows for engineering of the physical properties, the large number of deposition parameters, including different options for precursor gases, require a careful study of each of their impacts. In this contribution, we present measurements of low-temperature PECVD SiCN thin-films grown at different temperatures below 400 °C from SiH4, CH4 and NH3 as precursor gases by means of variable angle spectroscopic ellipsometry between 320 nm and 2500 nm and profilometry. Comparing possible ellipsometric models for fitting the measured data, it is shown that the Tauc-Lorentz model for amorphous semiconductors describes the refractive index throughout the whole wavelength interval. Low refractive indices between 1.7 and 1.8 as well as transparency above 600 nm are demonstrated, making SiCN layers suitable for near-infrared antireflection coatings on silicon. Profilometry is used to measure mechanical stress in the layers. Finally, the influence of deposition conditions on aging of the thin-films under ambient air is discussed.
Authors : Vilma Bursikova, Lukas Zabransky, Jiri Bursik, Milan Svoboda, Ivo Kubena, Pavel Soucek, Saeed Mirzaei, Petr Vasina
Affiliations : Department of Physical Electronics, Faculty of Science, Masaryk University, Kotlářská 2, 61137 Brno, Czech Republic; Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, 61662 Brno, Czech Republic
Resume : The aim of the present work was to study the microstructure and the mechanical properties of nanocomposite M-B-C (M=Mo, Ta, W) coatings which show a favorable combination of high stiffness, hardness and elastic modulus together with moderate ductility. The coatings were deposited on high speed steel and hard metal substrates using magnetron sputtering of three targets: B4C, C and M. Special focus was given on the analysis of the mechanical and tribological properties of the coatings. The mechanical properties were studied using nanoindentation tests under quasistatic as well as dynamic conditions. Microindentation tests were performed using indentation loads around 1N in order to study the fracture resistance of the coating/substrate system. The adhesion of the coatings to the substrates was studied using scratch tests. The details of microstructure in the vicinity of residual indentation prints were studied by transmission electron microscope (TEM). Thin lamellar cross sections for TEM observations were prepared using a focused ion beam (FIB) in SEM. The X-ray diffraction, performed on Rigaku Smartlab X-ray diffractometer with a fixed angle of incidence and the selected area diffraction patterns were used in order to determine whether the material is crystalline, nanocrystalline or amorphous.It was found, that the mechanical properties of these coatings depend on the nature of their microstructure. This research has been supported by Czech Science Foundation (15-17875S).
Authors : T. B. Serbeniuk, T. O. Prikhna, V. B. Sverdun, O. P. Ostash, B. D. Vasyliv, V. Ya. Podhurska, V. I. Chasnyk.
Affiliations : T. B. Serbeniuk - Institute for superhard materials NAS of Ukraine; T. O. Prikhna - Institute for superhard materials NAS of Ukraine; V. B. Sverdun - Institute for superhard materials NAS of Ukraine; O. P. Ostash - Karpenko physico-mechanical Institute of the NAS of Ukraine; B. D. Vasyliv - Karpenko physico-mechanical Institute of the NAS of Ukraine; V. Ya. Podhurska - Karpenko physico-mechanical Institute of the NAS of Ukraine; V. I. Chasnyk - State enterprise "Research Institute" Orion "
Resume : For vacuum electronics we received some composite materials based on powders AlN-SiC-Y2O3. In our work we used the powder SiC with dispersity 3 micron. The mixture based on powders AlN and 50 wt.%SiC was consisted of powder 2 ? 6 wt.%Y2O3. These materials were obtained by the method of sintering at the temperature 1850 °C in nitrogen atmosphere. By the method of Auger spectroscopy was established that some grains SiC are located evenly in structure. The yttrium-aluminum garnet was located between SiC and AlN grains. A slight increase of content from 2 to 6 wt.% Y2O3 in mixture determines the presence of almost continuous layers Y3Al5O12. These layers were formed at the grains boundaries of AlN and SiC, thereby separating grains. The calculation of density of materials showed that they have density is 2,74?2,80 g/cm3. The absorption of electromagnetic energy of materials was measured on frequencies 9,5?10,5 GHz and it was 35?65 dB/cm. The resistivity was determined at the temperatures from 20 to 800 °C. The ceramic materials exhibit high resistivity, in the range 106 ?107 Ohm at the temperature 20 °C. But materials with content 6 wt.% Y2O3 have a higher resistivity than with content 2 wt.% Y2O3. The resistivity decreases linearly for all materials and is near 7?104 Ohm with increasing temperature to 800 °C. The high absorption of the microwave radiation and high resistivity of materials allow to use them as absorbers in vacuum devices.
Cermets: production and properties : Prof. M.SZAFRAN
Authors : Konopka K.
Affiliations : Warsaw University of Technology
Resume : Zirconia ceramics are materials with desired properties for structural and functional materials. For possible applications the most important are the high flexural strength, high fracture toughness, high hardness, wear resistance and good corrosion resistance in acids and alkalis. Moreover, ZrO2- based ceramics are non-magnetic materials and good electrical insulators. In spite of the wide applications of ZrO2-based ceramics the various ZrO2-metal system composites are also developed. Composites of ZrO2-Ti system belong to this elaborated group of materials. Mostly due to the good combination of properties of both ZrO2 and Ti as thermal shock resistance, anti-corrosion, strength and high melting points ZrO2-Ti composites are considered for many applications for aerospace industries as well as biomaterials. Moreover, the zirconia is the transformation-toughened engineering ceramics. In zirconia-titanium composites Ti might have an influence on the transformation of tetragonal ZrO2 into monoclinic phase. The incorporation of Ti particles can also very efficiency improve the fracture toughness by mechanism of crack deflection or bridging. On the other hand, ZrO2-Ti system is the most complicated and demanding among of ceramic-metal composites. It is effect of complex structure, appearing of various compounds between initial Ti and TiO and ZrO2. Additionally, when to ZrO2 stabilizers are added (i.e. MgO, CaO, Y2O3, etc.) the new, complex compounds with special morphology and distribution are formed. Moreover, the process of ZrO2 and Ti powders consolidation to obtain the fully compacted, dense composite materials is complicated. In the present paper the result of producing and characterization of composites of ZrO2-Ti system are presenting. The ZrO2 is stabilized by Y2O3. Especially, the microstructure of composites is analysed. In composites, because of diffusion, in both direction Ti into ZrO2 and Zr into Ti the phase Ti -Zr-O is formed. Thise phase is taking part in crack propagation in composites. The toughening mechanisms with participation of Ti and phases based on Ti-Zr-O are discussed. ACKNOWLEDGEMENT This work was supported by The National Center of Science (NCN), project DEC-2013/11/B/ST8/00309.
Authors : Prikhna T. A.-1, Sverdun V.B.- 1, Basyuk T.V.- 1, Dub S.N.- 1, Ostash O.P.-2, Podhurska V.Ya.-2, Cabioch T.-3, Chartier P.- 3 Lucyna J.-4, Cyboron J.-4 , , IvasishinA.D.-2 ,Karpets M. V.-5, Kastornov A.-5, Moshchil V.-1, Varchenko V.- 5, Kovylaev V.- 5, Chirko L.-6, Chaykovskiy Y.-6, Litzkendorf D.-7
Affiliations : 1-Institute for Superhard Materials of NASU, Kiev, Ukraine; 2- Karpenko Physical-Mechanical Institute of the NASU,Lviv, Ukraine; 3- Universite de Poitiers, CNRS/ Laboratoire PHYMAT, France; 4-Instytut zaawansowanych technologii wytwarzania, Kraków, Poland 5-Institute for Problems in Material Science of the NASU, Kiev, Ukraine, 6- Institute for Nuclear Research of NASU, Kiev,Ukraine; 7-Leibniz Institute of Photonic Technology, Jena, Germany
Resume : The paper considers preparation processes of (Ti, Nb)-(Al,Si)-C MAX-phases-based nanostructural materials of 211, 312 structural types and their solid solutions in vacuum at 1.6×10-3 Pа, by pressureless synthesis in Ar at 0,1 MPa, hot pressing at 30 MPa and high temperature - high pressure sintering at 2 GPa. The results of the materials structure (using X-ray with Rietveld refinement, SEM and Auger spectroscopy), mechanical characteristics (macro-, micro- and nanohardness, fracture toughness, bending and compressive strength, Young modulus, logarithmic decrement of damping oscillations, friction coefficient), electrical conductivity, oxidation resistance in air (using DTA, TG), mechanical stability in hydrogen (at 600 oC), long-term stability in air (1000 h at 600 oC), stability in radiation environment and electrical resistivity study are presented. The characteristics of the obtained materials make them promising as interconnect material for hydrogen fuel cells, as damping materials, for slider bearings, for current collectors and even as polishing powders for jewelry stones, etc. The oxide film formed on the surface of the highly dense (ρ=4.27 g/cm3, porosity 1 %) material based on Ti3AlC2 (89 % Ti3AlC2, 6 % TiC, 5 % Al2O3) manufactured by hot pressing (at 30 MPa) made the material highly resistant in air at high temperatures: after 1000 hours of exposition at 600 °C and it demonstrated a higher resistance to oxidation than chromium ferrite steels (Crofer GPU and JDA types) which are used as interconnect material for hydrogen fuel cells.
Authors : 1-Barvitskyi P.P.,1-Prikhna Т.А., 2-Muratov V.B. , 2-Kartuzov V.V., 1-Sverdun V.B., 1-Dub S.N., 1-Loshak М.G., 1-Moshchil V.Е.,2- Karpets М.V., 1-Basyuk T.V.,1- Kozyrev A.V., 2-Kovylaev V.V.
Affiliations : 1-Bakul Institute of Superhard Materials of NASU, Kyiv,Ukraine; 2-Frantsevich Institute for Problems of Materials Sciences of NASU, Kyiv, Ukraine
Resume : This article focuses on the formation of composite materials based on α-AlB12 and AlB12C2 AlB40C4 under hot pressure (30 МPа) and high quasihydrostatic pressure (2 GPа) conditions at 1200-2100 оС. The interrelations between materials properties and structures are under the consideration. The results of the present study allowed us to conclude that the fracture toughness of α-AlB12 (98 wt.%, porosity 1.59%, density2.58 g/cm3) was lower than that of the AlB12C2–based composites (AlB12C2=70 wt.% BN=14 wt.% Al2O3=16 wt.%, porosity 5%, density2.42 g/cm3) prepared by hot pressing ( at 30 MPa). The fracture toughness (estimated under 49 N-load) of AlB12C2 –based composite was 7.6 MPа•m¹/² and the material Vickers hardness was about 20.1 GPа while the fracture toughness of α-AlB12 prepared under the same conditions was much lower: K1C = 4.2±0.5 MPа•m¹/² while the hardness was somewhat higher HV = 24.1 GPа. The fracture toughness of α-AlB12 sintered under high pressure (2 GPa) conditions was as well lower than that of AlB12C2. Addition of carbon (17 wt.%) to α-AlB12 and hot pressure synthesis leads to the formation of the composite material (AlB12C2=86wt.% and AlN_H=14wt.%, porosity 0.13%, density 2.7 g/cm3) with K1C = 5.9±1.4 MPа•m¹/² and Vickers hardness HV = 23.6±2.8 GPа. The material which according to the Rietveld of X-ray pattern refinement contains 99 wt.% of AlB40C4 (synthesized at 30 МPа) with density (2.64 g/cm3) which was somewhat higher than the theoretical one (2.64 g/cm3 ) demonstrated under the 49 N load 23.5 GPа hardness and 3.7 МPа•m¹/² fracture toughness. It should be mentioned that the higher density can be the result of Al2O3 presence in the material (as SEM study showed). The work was performed in the framework of the NATO Science for Peace G7050 project.
Authors : Vishwanatha Hire Math, Jayakumar Eravelly, Cheruvu Siva Kumar, Sudipto Ghosh
Affiliations : Department of Metallurgical and Materials Engineering, Indian Institute of Technology-Kharagpur, WB 721302, INDIA; Department of Metallurgical and Materials Engineering, Indian Institute of Technology-Kharagpur, WB 721302, INDIA; Department of Mechanical Engineering, Indian Institute of Technology-Kharagpur, WB 7201302, INDIA; Department of Metallurgical and Materials Engineering, Indian Institute of Technology-Kharagpur, WB 721302, INDIA
Resume : Metal matrix nanocomposites are of great interest due to the unabated thirst for high-strength to weight ratio materials in the field of automobile, aerospace and aviation industries. However, incorporating and dispersing the nano-sized reinforcements in the ductile matrix remains to be a major challenge. The problem is severe in the case of bulk nanocomposites. In the present study, a novel technique called Two-Step Ultrasonic casting was used to achieve unprecedented deagglomeration and uniform distribution of alumina nano-dispersoids in the Al-Cu matrix. It is a cavitation based technique through casting and solidification. It combines conventional contact-type and non-contact type ultrasonication. In this technique, during solidification, engulfing of particles is dominated over pushing and hence microstructure contains neither depleted zones nor (or) least grain boundary segregation of alumina dispersoids. Uniformly distributed dispersoids were mainly responsible for grain refinement and thus enhancement of mechanical properties. Significant improvement in distribution was possibly due to the combined effect of cavitation in the crucible and in the mould, leading to elimination of non-uniformity in the cooling rate at mesoscopic scale. The present work involves studies on microstructure, EBSD analysis, and hardness tests.
Authors : Makhno S.M, Lisova O.M., Gunya G.M., Gorbik P.P.
Affiliations : Chuyko Institute of Surface Chemistry NAS of Ukraine, General Naumov st., 17, Kiev, 03164, Ukraine, firstname.lastname@example.org
Resume : The graphene structures are rising in practical use and research, thanks to the complex of unique properties, high performance, low cost, manufacturability. The cost-effective technology for the development of high-quality graphene and composite materials is one of the prerogatives of current research. The aim is to study the synthesis and properties of composites nanoplates/(Ni-Co). The nanocomposites nanoplates/(Ni-Co) were obtained at a temperature 80oC by co-precipitation from a solution of hydrazine hydrate carbonates of nickel and cobalt and nanoplates. Nanoplates were obtained by electrochemical deposition in an electrolyte (KOH) of low concentration by transmission of a current from 6.0 to 60 mA/cm2. The samples of the system have expressed magnetic properties. The X-ray phase studies indicate the presence of phase nanoplates, cubic crystal system of nickel, hexagonal – cobalt reflexes and the absence of input precursors – carbonates. By the method of thermogravimetry it was found that the oxidation of metals in composites occurs at 295oC temperature and oxidation of nanoplates component starts at 600oC. The electrical conductivity of composites at low frequencies at room temperature up to 0.5 S/сm with the dispersed component density 2 g/сm3. The obtained nanocomposites can be promising for use in energy conversion, catalysis, screening and magnetic devices.
Composites based on metal and alloys : Prof. IRYNA UVAROVA
Authors : Kevin P. Anderson, Richard P. Vinci, Helen M. Chan
Affiliations : Lehigh University
Resume : Metal-ceramic composites ideally retain the hardness and stiffness of ceramic materials while improving fracture toughness. However, microstructural engineering of metal-ceramic composites is often limited by processing methods. The partial reduction of mixed oxides offers a simple and relatively inexpensive process for producing metal-ceramic composites. By generating the reinforcing metal in-situ, the structure and scale of the resulting composite can be controlled, potentially yielding nanocomposites. These principles were demonstrated in multiple material systems including Co-Ti-O and Cu-Al-O. By varying time and temperature, the process was engineered to control the scale of the metallic phase. Composite microstructures were characterized with SEM including EBSD, and TEM. Mechanical properties including modulus and hardness were then assessed through micromechanical tests including nanoindentation and microcantilever beam bending. The results will be discussed with respect to the morphology and scale of the composite and their effect on mechanical properties.
Authors : Olena Poliarus, Oleksandr Umanskyi
Affiliations : Frantsevich Institute for Problems of Materials Science (IPMS NASU)
Resume : The steady development of the current science and engineering requires both further improvement of traditional materials and design of novel ones capable to operate under the conditions of high temperatures and resist to the destructive action of aggressive forces. Today the development of composite materials based on the intermetallic NіAl, which exhibits high operation characteristics, is very important. Such materials are of particular interest in view of their application as high-temperature-oxidation-resistant protective coatings on parts of gas turbine engines. The developed materials are aimed at applying in the high temperature friction assemblies. The effect of the exposition time (1 min, 90 min) for high temperature (1000°С) oxidation of the NiAl-TiB2 and NiAl-ZrB2 composite material in air on the structure, phase composition and intensity of formation of oxide layers on the composite surface has been studied. The selective oxidation was observed. The initial composite structures was composed of a matrix from NiAl intermetallic containing regularly distributed grains of TiB2 or ZrB2. After oxidation of the composite on the NiAl matrix the continuous dense films were formed which correspond to the complex Al2O3 oxides and AlBO2 borate, whereas on the refractory TiB2 grains the volumetric globule-like Ti(Al)O and TiO2 oxides appeared. On ZrB2 grains the ZrO oxides are formed. To determine the relationship between the thicknesses of the oxides formed after oxidation, AES-analysis was used. The thickness of oxide layers on the matrix was established, it is equal to 80-180 nm, while that on the TiB2 grains was equal to 560 nm and on the ZrB2 grains - 980 nm. Therefore the intensity of oxide formation on boride grains is by seven times higher than that on the intermetallic matrix. These oxides can be used as solid lubricants and promote an increase of the wear resistance of materials.
Authors : Andreiev I.V., Bondarenko V.P.
Affiliations : Bakul Institute for Superhard materials National Academy of Sciences of Ukraine 04074, 2 Avtozavodska, Kyiv, Ukraine
Resume : Thus the most actual is creation of porous tungsten materials through which should diffusion the fused lithium. Also such materials should work as protective materials in a thermonuclear reactor. At Bakul institute for superhard materials scientific bases and technological aspects of receptions of powders of W up to 1000 microns which can be used as initial components for reception with the set porosity are developed. Revealing of influence of the sizes of particles of tungsten on their caking at use as the activator hydrogen-water steam the gas environment was the purpose of the present work. Sintering spent in the environment of hydrogen at temperature 1200 °С in classical flowing system and in the closed reactor. At sintering in the closed reactor after removal from samples of softener water for creation hydrogen-water steam the gas environment has been entered. Application hydrogen-water steam the gas environment has allowed sintered samples even from particles of tungsten more than 1000 microns. Such effect is caused by formation in the course of sintering gaseous tungsten based substance of type WO2(OH)2 which, reduction to tungsten in places of contact of particles, has allowed to provide between them physical contact. Thus the strength of prototypes tungsten materials more than doubled (from 30 to 70 MPa) for fine powders of tungsten. The use of mechanical activation surface tungsten powders allows significantly activate the process of sintering porous tungsten samples and reach the border values of compressive strength at most "coarse-grained" samples with tungsten powder fraction 500-1000 microns to 100 times higher (100 MPa) than raw powders. This provided the steel sample rates porosity of 40%.
Authors : O.Poliarus-1, O. Umanskyi-1, S.Chernega-2, V.Talash-1
Affiliations : 1-Frantsevich Institute for Problems of Materials Science (IPMS NASU); 2-National technical university of Ukraine "Kyiv polytechnic institute" (NTUU "KPI")
Resume : The aim of this work is development of new composite materials for protection of different details of shipbuilding industry and hydroenergetic equipment, floating oil and gas mining platforms from hydroabrasive and cavitation wear and also from action of corrosive medium. The investigation of phase and structure formation of composite materials and coatings on the base of intermetallic NiTi and NiAl with additives of refractory compounds, structural component optimal ratio determination and development of composite powders obtaining technology for gas thermal spraying of coatings are studied in this paper. Processes of plasma and detonation coatings structure formation and mechanisms of its corrosion, hydroabrasive and cavitation wear are investigated. The laboratory and production tests of developed composite materials and coatings in conditions of electrochemical corrosion in 3% NaCl water solution imitated seawater and also complex researches of materials on cavitation and hydraulic abrasive stability are conducted.
Authors : Swastika Banthia1, Siddhartha Das1,2, Karabi Das1,2
Affiliations : 1 School of Nanoscience and Technology, Indian Institute of Technology, Kharagpur, West Bengal, India-721302; 2 Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur, West Bengal, India-721302
Resume : This paper reports the influence of substrate and pulse electrodeposition (PED) parameters on macroscopic textures of as deposited Cu films. The as deposited single layers have been characterized by XRD, SEM, nanoindentation, and surface profilometer. The hardness and electrical resistivity of the as deposited single layers and Cu based FGM is evaluated and compared with that of annealed as purchased cold rolled Cu substrate under the same conditions. With increasing the current densities, the hardness of as deposited single layer of Cu film decreases due to porosity generated by hydrogen evolution at higher overpotential. Electrical resistivity is also affected by microstructure due to deposition parameters. When these Cu films were deposited from a same bath by varying texture along dimension, hardness has been increased by two times and resistivity decreases harmonically as the number of layers increases. Such a Cu based FGM possesses an optimal combination of electrical resistivity and mechanical properties.
Ceramic matrix composites : Dr. IRYNA BILAN
Authors : Mikolaj Szafran, Aleksandra Kedzierska-Sar, Emilia Pawlikowska
Affiliations : Warsaw University of Technology, Faculty of Chemistry, Noakowskiego 3, 00-664 Warsaw, Poland
Resume : Shaping of high performance materials including ceramic matrix composites by methods based on colloidal processing requires new, effectively working processing agents like deflocculants, binders, organic monomers, etc. The results of studies on the application of new water-soluble dispersants and monomers which are then used in the preparation of ceramic colloidal suspensions of high stability and low viscosity will be presented. The amphiphilic macromonomers, due to the proper ratio of the hydrophilic to hydrophobic fragments, play the role of not only an internal plasticizer, but they also modify the adhesion of such binders to the ceramic powder particles and substrates. The influence of chemical structure of these copolymers on the properties of ceramic matrix composites will be discussed. The authors elaborated the composition of suspensions based on ceramic and metal powders like Ni, W, Nb in the preparation of ceramic-metal composites by slip casting, gelcasting and subsequent sintering. The phenomenon of the heteroflocculation process in the slurries containing different particles will be also discussed. These studies were financially supported by the Warsaw University of Technology and National Science Centre Poland (Agreement No. 2014/13/N/ST5/03438.)
Authors : Christine Khoury , Oz M. Gazit
Affiliations : Chemical Engineering, Israel Institute of Technology, Haifa, Israel
Resume : Resins are a large class of crosslinked polymers that are widely used as heterogeneous catalysts and adsorbents. Traditionally these types of resins are made of functionalized synthetic polymers such as styrene-divinylbenzene copolymer. Recently the development of resins using naturally available polysaccharides is seeing a fast growth. The use of polysaccharides (i.e. chitosan and cellulose) as the backbone provides several benefits such as: 1) lack of solubility in most organic solvents and water, 2) inherent functionalization with pendent hydroxyl, carboxyl or amino groups, and 3) an abundant and sustainable polymer. These features make them good candidates as supports for enzyme, supports for metal catalysts and as adsorption materials. A prerequisite to using these polymers as high surface area frameworks is the prevention of their structure collapse, by the strong thermodynamic tendency to form inter- and intra- molecular hydrogen bonds. In order to overcome this limitation and obtain a high surface area material, supercritical CO2 drying is usually applied. In this method pressurized CO2, above its critical point (31.1 oC and 1072 psi), is used as an exchange solvent. The procedure entails exchanging the process solvent, usually ethanol, with liquid CO2. This is repeated several times until all the ethanol is removed and the CO2 can be discharged. The overall drying process takes about 3 days to be completed. In this work, we demonstrate a simple yet novel preparation method that allows us to obtain high surface area of chitosan (Cs) (currently up to 110 m2/gr) by incorporation of metal sites (Ti, Sn and Al). The obtained polymer composite is found to be highly stable even under high vacuum (10-3 mbar) and at 110 oC for over 12 hours, conditions which usually cause complete structure collapse. The general procedure includes dissolution of Cs in acidic media followed by neutralization in base and solvent exchange to a nonpolar-aprotic solvent. The ability of the polymer to swell in a polar environment and remain this way even after transfer to a nonpolar solvent is discussed with regard to the polymer amphiphilic nature. The dispersed swollen polymer is then infiltrated by metal precursors such as SnCl4, TiCl4 or tri-methyl-aluminum, which chemically react with available hydroxyls to form the composite framework. The results show that the BET surface area ranges between 25-110 m2/gr and is dependent on the condition of the dissolution process, the type of metal precursor and method of addition. . These results represent a major improvement in comparison to Cs without the metal addition, giving less than 1 m2/gr. The XRD indicate an amorphous structure, avoiding the formation of metal crystals. This is an indication that the metal sites are homogeneously dispersed within the polymer framework. XRD also indicates that the addition of metal prevents the Cs from recrystallizing, which suggests that the metal acts as a cross-linker. Results for TGA, ICP-OES, TEM-EDS, SEM-EDS, XPS and FTIR will be discussed. The coexistence of amine sites and covalently attached metallic sites are an interesting platform for promoting bifunctional or cooperative catalytic and adsorption properties, these are currently being assessed.
Authors : Paulina Wiecinska, Oksana Ryżyk, Emilia Pietrzak
Affiliations : Warsaw University of Technology, Faculty of Chemistry, Department of Chemical Technology, 3 Noakowskiego St., 00-664 Warsaw, Poland
Resume : Al2O3-ZrO2 composites have been prepared by gelcasting and subsequent sintering. Gelcasting allows obtaining high quality, complex-shaped ceramic elements by means of an in situ polymerization, through which a macromolecular network is created to hold ceramic particles together. Although the properties of the alumina - zirconia composites have been already known, the possibility of obtaining products with complex geometry can open up new application possibilities for the above composites. Alumina - zirconia composites combine the advantageous features of Al2O3 (high Young modulus and hardness) and ZrO2 (notable fracture toughness and bending strength). Additionally, gelcasting allows to obtain homogenous ceramic suspensions and as a result homogenous distribution of zirconia particles in alumina matrix and thus to achieve greater uniformity of the composite. At first, Al2O3-ZrO2 suspensions of different zirconia content (5% - 20wt%) have been prepared and characterized in terms of rheological properties and the selection of suitable organic additives. The main emphasis of the research was laid on the determination of polymerization conditions inside the ceramic slurries in order to obtain high quality green bodies. Then, the samples were sintered and characterized. SEM images confirmed the uniform distribution of zirconia particles. The project has been financially supported by the National Science Centre Poland (Agreement No. UMO 2014/15/D/ST5/02574)
Authors : Anne A. Y. Guilbert, Joao T. Cabral
Affiliations : Department of Physics and Centre for Plastic Electronics, Imperial College London, SW7 2AZ, London, United Kingdom; Centre for Plastic Electronics and Department of Chemical Engineering, Imperial College London, London SW7 2AZ, United Kingdom.
Resume : Many processes in organic photovoltaic devices, such as exciton dissociation and electron transport, are critically influenced by the packing of the acceptor molecules. We report the impact of the ternary solution phase behaviour on the film morphology and crystallization of a model polymer:fulerene system. We employ UV-Vis absorption spectroscopy, combined with sequential filtration and dilution, to establish the phase diagram for regio-random poly(3-hexylthiophene-2,5-diyl) and phenyl-C61-butyric acid methyl ester (PCBM) in chlorobenzene. The low polymer regio-regularity enables us to focus solely on PCBM crystallization. Films are systematically cast from one- and two-phase regions, with various polymer:fullerene ratios and concentrations in solution establishing a clear link between homogeneous and heterogeneous nucleation, and the role of pre-formed aggregates from solutions. Increasing annealing temperature reveals a highly non-monotonic nucleation profile, while the crystal growth rate increases steadilly within the range investigated, from 120-200°C. A maximum nucleation rate is observed at 170°C, all but vanishing at 200°C, well below the neat melting point of PCBM. UV ozonolysis is employed to vary substrate energy, and is shown to have a profound impact on crystallization, increasing nucleation rate and promoting a binary crystallization process. Exposure to light, under inert atmosphere, on the other hand, effectively suppresses homogeneous nucleation, but has a considerably smaller effect on heterogeneous nucleation, either from solution aggregates or substrate-driven. Our results establish a quantitative link between solution thermodynamics, crystallization and provide insight into morphological design based on process parameters in a proxy organic photovoltaic system.
Poster Session : Prof. IRYNA UVAROVA
Authors : Denys Savchenko, Eugene Paschenko, Olga Lazhevskaya, Andrei Chernenko, Nikolai Nekoval, Vyacheslav Bychihin, Sergey Golovchuk
Affiliations : V.Bakul Institute for superhard materials
Resume : Graphene-containig materials are one of the most interesting direction of the modern material science. They are widely used as functional and instrumental materials. Often, graphene in these materials are used as a filler, but not as a built-in structural component of one’s. The creation of material with self-organized graphene-like structure is a challenge for modern science. Presumably, self-organized material with graphene-like structure can have better mechanical, electrical and optical properties versus material with graphene filler. Usage of hybrid pre-polymers for synthesizing material with graphene-like structure are proposed. These pre-polymers consist of nano-scale organic and inorganic fragments. The catalytic activity of inorganic moieties in process of synthesis brought to formation of materials with self-organized graphene-like structure. Thus the graphene-like structure materials were obtained. Their structures were investigated with IR-spectra, Raman-spectra and WAXS. Based on study results the self-organisation mechanism of graphene-like structure obtaining was proposed. The light absorbency of graphene-like material was studied. The dependency between structural features of graphene-like materials and light absorbency was evidenced.
Authors : Yoonjong Yoo, Hongsoo KIm, Minwhee Cho*,Hyunjae Lee*
Affiliations : Korea Institute of Energy Research(KIER) *Environmental R&D center, ENBION Inc.
Resume : This paper is about ceramic gasket manufacturing technology that can be used the extreme temperatures. This gasket is manufactured using ceramic fiber and talc main raw materials, and inorganic content is about more than 95 percent. Therefore, gasket has thermal stability, chemical and corrosion resistance and superior properties. So the chemical plant, high pressure thermal processing, steam lines and can be used. In this study, paper manufacturing method applied for preparation of the ceramic gasket sheet and it's a new economic process will be. Inorganic fiber, talc and binders evenly distributed in the waters for manufacture the gasket. Then dehydration on the wire mesh by supplying the slurry, and compression, through drying process completed the gasket for extreme temperature. The characteristics of manufactured during the experiment are density 1.88g/cm3, tensile strength 0.15 kg/mm2, compressibility 39%, recovery 17% and ignition loss 6.55% at 1,000oC. And there was no pressure drop when 10 minutes in conditions of 150LB(two inch) 10kgf/cm2 nitrogen. All the additives are being evenly distributed to the surface of the gasket, and each other's bonds have been completed successfully, and the applicability by paper manufacturing process. It has been confirmed that enough.
Authors : Yongsan An, Woong-ryeol Yu
Affiliations : Department of Materials Science and Engineering and Research Institute of Advnaced Materials (RIAM), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744, Republic of KOREA
Resume : Shape memory polymers (SMPs) are the materials which have ability to recover their permanent shape from temporary one by external stimulus like heating. Potential applications of SMPs to functional products such as self-deployable antenna and self-folding origami have been suggested, however, their processability is not good enough to manufacture those complex structures. In this research, 3D printing method was used to fabricate complex 3D structures of SMPs. As for materials, an epoxy type of SMP and nanomaterials (nanoclays and nanocarbons) were used. Here nanoclays and nanocarbons were used to increase the viscosity of pre-cured SMPs, whose viscosity was too low to maintain continuous filament after printing. Pre-cured SMP nanocomposite showed the shear-thinning behavior so that its viscosity was lowered enough to be printed from a nozzle of small diameter. After printing, the printed SMP nanocomposites was solidified and cured by heating in a chamber. First, dog-bone shape specimens were printed via 3-axis controlling system and cured at high temperature. Their shape memory behavior and thermomechanical properties were characterized. Then, complex surface shapes designed by using origami tessellations were printed to investigate a possibility of developing morphing structure using 3D printing of SMPs.
Authors : I. Gab-1,T.Stetsyuk-1, V. Malyshev-2, N. Uskova-2, A. Gab-3, M. Gaune-Escard-4
Affiliations : 1-Frantsevich Institute for Problems of Materials Science of NASU, Kiev, Ukraine; 2-Vernadsky Institute of General and Inorganic Chemistry of NASU, Kyiv, Ukraine; 3-National Technical University of Ukraine "Kyiv Polytechnical Institute", Kyiv, Ukraine; 4-Aix-Marseille University, Ecole Polytechnique, IUSTI, CNRS, Marseille , FRANCE
Resume : It is shown that the cathode products of electrolysis of melts based on a eutectic mixture of sodium chloride and lithium fluoride as well as melts based on sodium tungstate, in which oxides of molybdenum (VI) or tungsten (VI), and lithium or sodium molybdate, tungstate, and carbonate are dissolved, can be molybdenum, tungsten, their bronzes and carbides, and also carbon. It is established that the phase composition of electrolysis products is determined by the concentration of carbonate in the melt. Particular conditions of deposition of coating of molybdenum and tungsten carbides on carbon, nickel, and copper materials are determined. Molybdenum carbide coatings are deposited from Na2WO4?Li2MoO4?Li2CO3 electrolyte at equal (within 2.5 mol.%) concentrations of lithium molybdate and carbonate. However, their concentrations should not exceed 10 mol.%.
Authors : Naidich Yu.V., Poluyanskaya V.V., Sydorenko T.V.
Affiliations : I. Frantsevich Institute of Problems of Materials Science of NAS of Ukraine
Resume : The investigations of wetting in vacuum of tin dioxide ceramics by some pure metal melts (Ag, Cu, Sn, In, Ga, Pb) were carried out in this work. The most of these metals doesn’t wet of ceramic substrate at the temperature before 900 ºC (contact angles ~ 120 – 135 degrees). Such metals as In, Ga, Sn upon further heating (T = 950 – 1000 ºC) form a low contact angles (20 – 25 degrees). The Silver at 1000 ºC in vacuum doesn’t wet tin dioxide ceramic substrate (120 degrees). This result is close to the value of the contact angle for Ag – SnO2 system in the air (110 degrees). The Copper is demonstrated a very interesting wetting result: at the temperature before 1000 ºC contact angles is about 130 degrees, in range 1000 – 1100 ºC – contact angle of Cu decreases up to 65 degrees, and at 1180 ºC – up to 58 degrees. The microstructures of contact zone of all ceramics-metal systems were investigated.
Authors : Aurora Gomez-Martin (1, 2), M.Pilar Orihuela (1-3), Julian Martinez-Fernandez (1,2), Jose A. Becerra (3), Ricardo Chacartegui (3), Joaquin Ramirez-Rico (1,2)
Affiliations : 1 Departamento Física de la Materia Condensada, Universidad de Sevilla, Avda. Reina Mercedes SN, 41012 Sevilla, Spain. 2 Instituto de Ciencia de Materiales de Sevilla (CSIC-Univ. Sevilla), Avda. Américo Vespucio 49, 41092 Sevilla, Spain. 3 Departamento de Ingeniería Energética, Universidad de Sevilla, Camino de los Descubrimientos SN, 41092 Sevilla, Spain.
Resume : Interest in porous ceramics for industrial applications has grown due to their combination of desirable properties. These properties depend on microstructural parameters, thus a thorough knowledge of the microstructure is searched. X-ray tomography is a useful and advanced non-destructive technique for providing a three dimensional visualization of the microstructure of porous media through a combination of 2D sectional images. Biomorphic SiC (bioSiC) is a porous ceramic material obtained by Si melt infiltration of carbon preforms from wood pyrolysis. The resulting material retains the original wood’s anisotropic and hierarchical porosity, which is difficult to obtain through other routes and is interesting for a variety of applications. In this work, we use X-ray tomography to reconstruct a real network representation of the microstructure of a pine-wood derived bioSiC to be further used as a model geometry for finite difference simulation of transport properties. Thermal conductivity and permeability simulations were carried out based on the reconstructed image after the segmentation step. Results of high resolution X-ray tomography-based simulations allow to obtain a greater understanding between properties and microstructure, and to simulate a visualization of these processes taking place in complex porous materials. We further advance in this characterization by measuring these transport properties experimentally and relating them to the bulk and simulated values.
Authors : S. Kratro
Affiliations : Department Electrophysics, Faculty of Radiophysics,Electronics and Computer Systems, Taras Shevchenko National University of Kyiv
Resume : Interest in metal nanostructures stems from their unique optical properties related with single-particle or collective plasmons. Thе aim is focused on optical properties of gold nanorods and silica/gold nanoshells, whereas the synthesis protocols and biomedical applications are discussed shortly. The effects of the gold nanoshells structural polydispersity and the surface electron scattering in a thin metal layer on the resonance light scattering spectra are studied theoretically and experimentally for the silica/gold nanoshell water colloids. Both the gold nanorods and nanoshells are exceptionally biocompatible nanomaterials, which surface can be easily functionalized by key probe molecules such as antibodies, oligonucleotides, biotin.
Authors : Ihor Polishko (1), Yegor Brodnikovkyi (1), Dmytro Brodnikovskyi (1), Mykola Brychevskyi (1), Bogdan Vasyliv (2), Viktoriya Podhurska (2),Oleksandr Vasylyev (1)
Affiliations : (1) Frantsevich Institute for Problems of Materials Science of NASU, Krzhizhanivsky str. 3, 03680, Kyiv, Ukraine (2) Karpenko Physico-Mechanical Institute of NASU, Naukova str. 5, 79601, Lviv, Ukraine
Resume : Solid oxide fuel cell (SOFC) is of the most promising technology for electricity production due to direct conversion of chemical energy of the fuel and oxidant into electricity and heat. For the planar designed SOFC, usually anode is a support of a whole cell. The main electrochemical reaction of fuel oxidation is occurred on the anode side. Today, 8YSZ-NiO is one of the commonly used compositions for anode application. Anode material should meet some contradictory requirements. On the one hand – high strength to provide SOFC manufacturing and its further reliable operation. On the other hand – high porosity to ensure venting gases (fuel supply and removing of reaction products). In present work the traditional anode-support ceramic component 8YSZ was replaced by much stronger 3,5YSZ. The anode strengthening allows to increasing its porosity. To provide the additional porosity in 3,5YSZ-60wt.%NiO anode were added the pore-former (starch) in varying amounts (from 11vol.% to 32vol.% ). The influence of pore-former content on anode-support structure, mechanical and electrical properties were studied. It was shown that increasing pore-former amount leads to increase open-porosity, while mechanical strength and electrical conductivity were reduced. It was found, that the optimal pore-former content for 3,5YSZ-60wt.%NiO anode was 18-vol.%. These anodes with 43% of open porosity provided mechanical strength of 74 MPa and electrical conductivity of 0.93∙10^6 Sm/m.
Authors : Justyna Zygmuntowicz, Joanna Łoś, Aleksandra Miazga, Katarzyna Konopka
Affiliations : Warsaw University of Technology Faculty of Materials Science and Engineering 141 Woloska Str. 02-507 Warsaw Poland
Resume : The aim of this paper was to characterize the microstructure and selected properties of ZrO2-Ni composites. The composites were prepared from the powder mixture contains: 90 vol.% of ZrO2 and 10 vol.% of nickel powder. The samples were formed by uniaxial pressing. Two series of samples were fabricated with different sintering temperatures: series I was sintered at 1400 °C and series II was sintered at 1600 °C. Sintering process was conducted in an argon atmosphere. In the experiments the following powders were used: ZrO2 powder stabilized by 3 mol% Y2O3 from TOSOH ZIRCONIA TZ-3YS-E of an average particle size less than 100 nm and density 5.88 g/cm3 and Ni powder from Sigma-Aldrich of an average particle size 1.5 µm and density 6.67 g/cm3. The structure of samples was examined by X-ray diffraction (XRD) after sintering. The microstructure of composites were investigated by scanning electron microscopy (SEM). The chemical composition was examined in microareas on a cross-section of the sample by EDS. Quantitative description of the microstructure of the ZrO2-Ni composites was made on the basis of SEM images on the cross-section using computer image analysis. The physical properties of prepared composites were measuring by Archimedes method.
Authors : Cezary Czosnek (1)*, Mariusz Drygaś (1), Andrzej Huczko (2), Jerzy F. Janik (1)
Affiliations : (1) AGH University of Science and Technology, Faculty of Energy and Fuels, al. Mickiewicza 30, 30-059 Krakow, Poland; (2) University of Warsaw, Department of Chemistry, 1 Pasteura St., 02-093 Warszawa, Poland *email@example.com
Resume : Silicon carbide SiC is known of many advantageous material properties. Specifically, its good thermal conductivity coupled with a chemically/mechanically robust nature predestine the compound’s porous materials forms for utilization as catalyst supports in many exothermic and high temperature processes. Herein, reported is a study on thermal decomposition of a commercially available polycarbomethylsilane in the mixture with carbon/silicon carbide C/SiC nanocomposites towards more complex compositions. The starting C/SiC nanopowders were prepared by a two-stage aerosol-assisted synthesis method. They were first soaked in a toluene solution of polycarbomethylsilane. Upon volatiles evacuation, the green solid was pyrolyzed at 1300 °C, Ar, 1 h, resulting in polymer decomposition with secondary SiC formation, the latter phase acting as a binder for the initial C/SiC composite particles. The final products were characterized mainly by powder XRD diffraction and SEM examination. Low temperature nitrogen adsorption study was carried out to determine their standard surface properties. The latter were consistent with mesopore characteristics of the resulting hierarchical SiC(C/SiC) products. Acknowledgment. This work was supported by AGH University of Science and Technology Grant No. 126.96.36.199.
Authors : Prof. Dr. Chernega S.1, Poliakov I.1, Krasovskiy M.2
Affiliations : 1National Technical University of Ukraine "Kiev Polytechnic Institute", Kiev, Ukraine e-mail: firstname.lastname@example.org; email@example.com 2The Frantsevich Institute for Problems of Materials Science of NAS of Ukraine, Kiev, Ukraine
Resume : In this paper was investigate the structure, phase composition and properties of boride coatings obtained on hard alloys T15K6. Investigate the structure and characteristics boride and complex saturation with boron and copper coatings on hard alloys T15K6 obtained in environments powder with the participation boron carbide and copper containing powder Cu2O or Cu3P. X-ray phase analysis established that at diffusion saturation in the surface layers of hard alloys formed phases: TiB, WB, CoB, WC, TiC and respectively Cu. At the addition in environment for boriding copper containing powder identification of clear lines Cu (111) (200) (220). X-ray analysis confirmed the local distribution of copper in the surface zone boride coatings obtained after complex saturation with boron and copper. Established that boriding and complex saturation with boron and copper allows in 1.5 – 2.5 times increase microhardness of the surface layers of hard alloys, which in turn leads to increased wear resistance. After boriding on the surface hard alloys obtain coating microhardness which is 31 – 33 Gpa, base – 13 – 13.5 GPa. At the complex saturation with boron and copper obtain coating microhardness which is 24 – 25 GPa. Boriding and complex saturation with boron and copper allows in 2 – 2.5 times increase the microhardness of the surface layers of hard alloys, that in turn leads to increased wear resistance. Investigations have shown that the boride coating allow in 2 times increase the term of operation rollers. When the rollers working without coating can be made of 10 tons aluminum profiles, whereas at the application of the boride coatings is reached value of 21 tones.
Authors : Parkhomey O.R., Pinchuk N.D., Sych O.E.
Affiliations : Frantsevich Institute for Problems of Materials Science of NASU, Kiev, Ukraine,
Resume : Today hydroxyapatite keeps the leading position as a material for bone tissue engineering. Porous glass-ceramic composite materials based on biogenic hydroxyapatite and sodium borosilicate glass (weight ratio was 1.0/0.46) have been prepared from starting powders with different particle sizes (< 50 ?m and < 160 ?m) at sintering temperature 800 ºC. It was established that total porosity of the glass-ceramic samples practically did not depend on the particle size and was 33 %. Glass-ceramic composite materials resorption rate investigation was carried out in an isotonic saline solution at 36.5 °? in thermostat and followed by determination of mass loss. It has been established that the glass-ceramic composites resorption rate increases by 1.5 times with increasing of initial particle size. At the same time, increasing the duration of biosolubility experiment from 2 to 7 days largely affects on the composites prepared from more dispersed charge. Also it is shown that the change in pH of saline in the presence of the samples only slightly dependent on the initial particle size of the charge. However, the pH increases from 7.9-8.1 to 8.4-8.6 for longer staying samples in saline due to the leaching of the composites? amorphous component. Thus, prepared composites exhibit certain resorption rate and may be promising for the replacement of bone defects, when necessary use of bioactive material with resorbed properties.
Authors : Marcin Malek*, Pawel Wisniewski, Joanna Szymanska, Jaroslaw Mizera, Krzysztof Jan Kurzydlowski
Affiliations : Faculty of Materials Science and Engineering, Warsaw University of Technology, * Corresponding author: firstname.lastname@example.org
Resume : From a few years in Poland, scientists are working about new technology of shale gas exploitation and extraction. This paper is one of the first work to determine new composed fracturing fluids based on water and theirs rheological properties. Fracturing fluid is a substance, which is injecting into a wellbore, using high pressure, to form new slots or cracks in shale rocks. After this process fracturing fluid must be removed from the wellbore to allow the process of shale gas extraction. This substance are supporting the process of pumping proppants into the beds, and must meet specific conditions depends on: characterization, location and depth of beds. Together with proppants form suspension facilitating the extraction of gas from rocks. This work present rheological properties such as: viscosity, dynamic viscosity, pH and density of new researched fluids. To modification fluid parameters poly(vinyl alcohol) with molecular weight 26000 g/mol, and hydrolysis degree 88% as a 5 wt.% water solution were added in amount: 0,3; 0,5; 0,7; 1;1,2 and 1,5 wt.%. This basic study shown that obtained results are acceptable for industry, but needs a few modification to future application. Key words: extraction, fracturing fluids, proppants, rheological properties, shale gas, Financial support of BLUE GAS financed from The National Centre for Research and Development- Project “ Optimizing the lightweight high strength and low specific gravity ceramic proppants production technology maximally using naturally occurring Polish raw materials and fly ash , No. BG1/BALTICPROPP/13 is gratefully acknowledged.
Authors : Fabio Coral Fonseca, Paulo Sergio Martins da Silva, Debora Marani, Daniel Zanetti de Florio, Vincenzo Esposito
Affiliations : IPEN, DTU, UFABC
Resume : In this study we present results on new composites comprised of O2--ion conductors and non-oxide ceramic second phases. Such materials are relatively less studied than other ceramic-based composites, but represent an interesting research topic due to interesting phenomena arising from the distinct nature of chemical bonds (ionic and covalent) of component phases and its influence on both the microstructure and transport properties. Such composites can couple interesting properties from each phase into high-performance materials for applications as sensors, electrochemical devices, and thermochemical conversion of fuels. Two systems have been investigated: yttria-stabilized zirconia (YSZ) / TiN and gadolinia-doped ceria (CGO) / ZrB2. In both systems, advanced sintering techniques such as spark-plasma sintering and sintering under reducing conditions were used for obtaining both dense and highly porous samples, depending on the composite and desired application. In the YSZ/TiN composites attention was given for the electrical conductivity of dense samples and its dependence on the oxygen partial pressure aiming at applications such as solid oxide fuel cell anodes. Main results show that samples attained very high electronic conductivity at volume fractions of ~25 vol.% of TiN and good resistance to oxidation up to 600 °C in air. The CGO/ZrB2 was investigated aiming at high-temperature porous catalysts for solar driven thermochemical water splitting. In this application, ZrB2 was used as a sintering inhibitor for CGO. Dilatometry results evidenced that in reducing conditions, in which CGO display fast mass diffusion processes, the composite retained high porosity at 1600 °C, preserving a high surface area of the catalytic phase (CGO).
Authors : Xin Cui 1, Xia Ni 1,*, Yan Zhang 2,*
Affiliations : 1 Institute of Nanoscience and Nanotechnology, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China. 2 School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, China.
Resume : Piezoelectric nanogenerator based on oriented assembly of nanowires is a dominant device developed for converting mechanical energy into electrical energy. By finite element method, the nanogenerator based on lead zirconate titanate (PZT) nanowires is modeled to evaluate its capacitance, charge density on the top electrode and open circuit output voltage. The investigation on size-dependent performance demonstrates that the output voltage of the device increases with the increase of the length as well as the decrease of the diameter. The output performance depends on the types of PZT materials. When adopting PZT-7A as the piezoelectric materials, the nanogenerator could obtain a larger output. In addition, our investigation also shows that the device?s thickness affects slightly the output voltage. Compared with PMMA, PDMS could give rise to higher output voltage. Based on different types of PZT materials and polymers, our study presents the output voltage of the nanogenerator by changing of the PZT nanowire?s length, diameter, and the nanogenerator?s thickness. These results will be of crucial importance for optimal of the performance of the flexible nanogenerator based on oriented nanowire assembly.
Authors : Kryachek V.M., Chernyshev L.I., Gudymenko T.V., Ragulya A.V., Fedorova N.E.
Affiliations : Frantsevich Institute for Problems of Materials Sciences of National Academy of Sciences of Ukraine
Resume : The the main trends in synthesis of nanoscale powders and nanostructures of basic and transition metal nitrides had been analyzed. Chemical methods are generally more versatile and productive. The relatively simple and cheap chemical technologies are well developed for nitride nanosize powder of Si, Ti, Al, Nb and other elements. Among them Plasma-chemical synthesis, Thermal decomposition of unstable precursors, Self-propagating high temperature synthesis (SHS) are most productive and scalable. Chemical methods allow producing pure nitride nanosize powders and composite systems Si3N4-CrN, TiN-AlN, AlN-ZrN and others. Physical methods (evaporation, condensation) or gas phase synthesis (CVD) and (PVD) based on the evaporation of the initial components and their subsequent condensation in the reactor under controlled temperature and gas environment conditions. When treated in nitrogen, metals such as Al, Ti, Cr, V, Mo or their alloys yield powders of the required composition with sizes ranging from 50 nm to 100 micrometers. In recent years, there have been developing several methods based on electrochemical reactions in the medium of organic precursors. This approach has been applied in the synthesis of nanosize nitrides VN, CrN, GaN, Si3N4, TiN, AlN, BN. Powders of W2N, CrN, TiN, GaN, VN, NbN with particle size of 50-200 nm and a surface area in the range of 20-200 m2/g have been manufactured by so-called glass-carbide method. Some of these methods considered prospective for the manufacturing of various nanostructures such as nanofibers, whiskers, nanowires, nanotubes, onions etc. had been presented.
Authors : Ragulya A.V-1., O.B. Zgalat-Lozynskyy-1, Kryachek V.M.-1, Chernyshev L.I.-1, Gudymenko T.V.-1,Avetisian D.A.-2
Affiliations : 1-Frantsevich Institute for Problems of Materials Sciences of National Academy of Sciences of UKraine, Kyiv,Ukraine; 2-Taras Shevchenko National University, Kyiv, Ukraine
Resume : Among the field assisted sintering (FAST), the microwave (MWS) and spark plasma sintering (SPS) are considered in details. Both processes are intensively developing worldwide. Nanostructured nitride ceramics is in the focus of applied research because these materials promise solve many technical problems such as substantial improvement of required properties and reduction of power consumption. Two approaches will be discussed as appropriate to maintain nanosize grain structure: optimization of temperature-pressure-time protocol of sintering and reaction-driven sintering. The SPS is a rapid rate consolidation technology where the effect of electromagnetic field married with the effect of applied pressure. The SPS of titanium nitride based ceramics will be presented for the particulate systems Si3N4-TiN, TiN-AlN and reaction system TiN-TiB2. During the microwave sintering of nanosize powders the appearance of surface related effects are expected to be most bright, which influence on grain boundary diffusion controlled densification and grain growth. Intensive densification of nanostructured high melting nitride materials could be attributed to liquid phase appearance in the necking zones between particles on the initial densification stage, where the intensity of electric field gets maximal value. Both SPS and MWS techniques are considered prospective for development of nanostructures ceramics and nanocomposites with grain size bellow 50 nm and top combination of properties.
Authors : Iurii Falchenko, Anatolii Ustinov , Lidia Petrushinets ,Tatyana Melnichenko
Affiliations : THE E.O. PATON ELECTRIC WELDING INSTITUTE OF THE NATIONAL ACADEMY OF SCIENCES OF UKRAINE
Resume : In the diffusion welding of difficult-to-deform materials such as composites, the application of intermediate multilayer foils, which have alternating layers of elements that form intermetallics, allows for production of a permanent joint under milder conditions. In this paper, the processes occurring in the joint zone during DW of Al?5 wt.%Mg+27 wt.%Al2O3 composite material through the Al/Cu interlayer were studied. It was shown that, while heating of such a foil, phase transformations that are due to the reaction diffusion of elements, run in it. At heating multilayer foils under a continuously applied external load, the materials are plastically deformed. It is established that the intensity of foil plastic deformation at a specified load non-monotonically depends on temperature. It is shown that welding temperature is determined by the temperature at which MF can undergo superplastic flow under the impact of applied pressure. Acknowledgements.This work has received funding from the EU FP7 Project “Super Light-Weight Thermal Protection System For Space Application" (LIGHT-TPS) under Grant Agreement no. 607182
Authors : Barantsova A.V., Grishchenko V.K., Bus'ko N.A., Gudzenko N.A., Myshak V.D.
Affiliations : Institute of Macromolecular Chemistry of NASU
Resume : It is known that high physico-mechanical properties of polydieneurethanes are due to the presence in their molecules groups which are able to association. The optimal version of obtaining polydieneurethanes is synthesis of isocyanate forepolymers. An isocyanate forepolymer is obtained by interaction of oligodienedihydrazones with diisocyanate in molar ratio 1:2. It is found at that the cyclization of acylhydrazone groups under action of diisocyanate takes place with forming oligomers containing 1,3,4-oxadiazoline cycles. The reaction course is confirmed by the data of IR-spectroscopy. The study of the process of forepolymer curing showed that the best technological and mechanical characteristics of polymeric materials are achieved at using aromatic diamines as chain extenders. A range of polymeric materials were obtained which characterized high physico-chemical properties, depending on the ratio of elastic (forming on the base of diene chain) and hard (forming on the base of diisocyanate and a chain extender) blocks. The hydrophobicity of diene blocks in a polymer chain explains the fact that elastomers obtained have swelling as low as 10-100 times compare with urethane elastomers based on polyethers. It is shown that the elastomers obtained, depending on oligodienedihydrazide molecular weight, exceed on hydroabrasive wear stainless steel as much as 4-20 times. The changes of the stability coefficient are connected with changing of the oxadiazolinylcarbamate group (formed at interaction of acylhydrazones with isocyanates) structure which are transformed to acylsemicarbazide ones under the influence of liquid corrosive mediums. It is confirmed by the IR- and UF- spectroscopy methods. The materials are obtained with a wide property range: from stick adhesives to abrasive- and corrosive resistant elastic coatings by virtue of replacement of a reactive group.
Authors : Sergey I. Pokutnyi
Affiliations : Chuiko Institute of Surface Chemistry of NASU
Resume : The effect of a significant increase in the exciton binding energy of spatially separated electrons and holes (hole moves in the volume of the quantum dot (QD), and the electron is localized on a spherical surface (QD - matrix)) in nanosystems containing germanium QDs grown in a matrix of Si by compared with the binding energy of an exciton in a single crystal of Si. It was found that in such nanosystem in the conduction band of the Si matrix is first a zone of states of electron-hole pair that with increasing radius of the QD becomes a zone of exciton states, located in the band gap of Si matrix . It is shown that the mechanisms of absorption in Ge/Si heterostructures with QDs Ge caused by intraband transitions of electrons between quantum-levels of the electron-hole pairs, arranged in the conduction band of the Si matrix and intraband electron transitions between quantum-exciton levels located in the band gap of silicon matrix, and and interband electron transitions between quantum-level Eh(a) (a – radius QD), located in the valence QD Ge, and quantum-levels of the electron-hole pairs, and interband electron transitions between quantum-level Eh(a) and quantum-exciton levels located in the band gap of silicon matrix . Built here the theory allows for the absorption spectra of Ge/Si heterostructures with Ge QD detected experimentally at room temperature electron transitions between exciton states of space - separated electrons and holes (the primary (n = = 0) and By changing the parameters of the Ge/Si heterostructures with QDs Ge (radii a QD, as well as the ratio of the effective mass of the quasiparticles, can be directed to vary the position of the energy levels of the electron-hole pairs and excitons (of spatially separated electrons and holes ), the exciton binding energy, the width of the exciton bands, as well as the energies of transitions in exciton bands. The latter circumstance, as well as the effect of a significant increase in the exciton binding energy, apparently, opens up new possibilities in the use of nanoheterostructures as the active region nanolasers working on excitonic transitions at room temperature
Authors : Iryna Gnatenko, Volodymyr Bondarenko, Volodymyr Botvinko
Affiliations : V. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine 2 Avtozavodska Str. , 04074, Kyiv, Ukraine Department of Technology of cemented carbides and structured of composition materials e-mail:email@example.com
Resume : For the manufacture of high-quality cemented carbides recommended that to shorten the process of growth of carbide WC and to eliminate the growth of individual grains. To obtain a uniform fine grained structure often used of inhibitors, such as chromium carbide Cr3C2 at 0.5 - 1% by weight of the alloy. Alloys containing 20% of binder by weight during sintering have very intense grain growth. The paper presents the results of studies on the effect of dopant Cr3C2 on the microstructure of WC-20 wt. % Ni. It has been found that addition of chromium carbide in the cemented carbide WC-20 wt. % Ni reduces the size of grain WC. The cemented carbide without the addition has grain size 1.85 microns and doped alloys - 1.65 microns. Increasing the content of chromium carbide of 0.5 to 1% by weight does not affect the average grain size in the alloy. Was determined the contiguity in the alloy. The alloy of WC-20 wt. % Ni contiguity was 0.5, and the alloy in WC-20 wt. % Ni + 0,5(1) wt. % Cr3C2 contiguity was 0.52. Was found that the structure of the alloys after exposure to chemicals during etching (Murakami's reagent + FeCl3) was very different. In the structure of cemented carbides without the addition were found of grain WC that fall out after etching. In the structure of cemented carbides with the addition of chromium carbide 0.5 and 1% by weight the grain of WC does not fall. The explanation for this phenomenon may be different resistance of grain boundaries WC-WC to the effects of chemicals. These assumptions require further research.
Authors : M. Sokol, S. Kalabukhov, N. Frage
Affiliations : Ben-Gurion University of the Negev
Resume : High pressure (up to 450MPa) spark plasma sintering (HPSPS) technique allowsto fabricate polycrystalline ceramics at relatively low temperatures with short sintering time.The specimens obtained by HPSPS technique display submicron structure and a good combination of optical and mechanical properties; comparable with the best results reported in literature for a two-stage fabrication process (pressureless sintering followed by hot isostatic pressing or vacuum sintering).Our recent experimental results ondensification of magnesium aluminate spinel (MAS) and yttrium aluminum garnet (YAG)indicate a strong effect of the applied pressure on the microstructureof the sintered ceramics.At the same time,SPS under high uniaxial pressure has raised some fundamental questions related to the microstructure evaluation, for instance,grain size increasingwith the applied pressure. The present work focuses on the understanding of sintering behavior during HPSPS-process, mainly on the stress induced grain growth mechanism
Authors : S. Kalabukhov,M.Sokol,M.Boaron, S.Danon, N. Frage
Affiliations : Ben-Gurion University of the Negev
Resume : Zinc Aluminate Spinel, ZnAl2O4, which is also designated as gahnite, is a ceramicsemiconductor with a band gap of about 3.9 eV and large absorbance in the UV region, thus it has emerged as an alternative choice for transparent conducting oxide when doped with transition metal ions.Polycrystalline transparent gahnite was fabricated from pure oxides with and without 0.8 wt.% LiF additives.The process was conductedby Spark Plasma Sintering (SPS) technique.The effect of the SPS parameters (temperature, heating rate and holding time) on the kinetics of gahnite synthesisduring SPS treatment is discussed as well as the optical and mechanical properties of the transparent specimens. It was established that the LiF doped specimens can achieve greater densification at the same time and temperatureas the un-doped samples.Nevertheless,above sintering temperature of 1100°C abnormal grain growth was observed in the LiF doped samples. As a consequence,large grains and lower mechanical properties were observed.
|Start at||Subject View All||Num.||Add|
NEW LIGHT WEIGHT METAL AND CERAMIC MATERIALS FOR THERMAL PROTECTION SYSTEMS VOR VARIOUS SPACE APPLICATIONS (RESULTS OF FP7 : Dr. IRYNA BILAN
Authors : A) M. Parco and I. Fagoaga B) L. Silvestroni C) I. Belan, I. Neshpor and G.A. Frolov D) M. Kütemeyer and T. Rheimer
Affiliations : A) Fundación Tecnalia Research & Innovation, Donostia-San Sebastián, Spain B) CNR-ISTEC, Faenza (RA), Italy C) Frantsevich Institute for Problems of Materials Science NAS of Ukraine, Kiev, Ukraine D) Institute of Structures and Design / Ceramic Composites and Structures, DLR, Stuttgart, Germany
Resume : Thanks to their extremely high melting point above 3000°C and their unique combination of thermo-physical and engineering properties, ultra-high temperature ceramics (UHTCs) and coatings on their basis are envisaged as promising candidates for application at very high temperature. Among various compounds, ZrB2 has several advantages over other metal-based borides and carbides. One critical issue in the production of ZrB2-based ceramics is the achievement of fully dense bodies/coatings, which is the base-line condition to achieve good thermo-mechanical properties and oxidation resistance. Owing to the strong covalent bonds featuring all UHTCs, temperature above 2000°C and the application of pressure are required to densify these compounds. However, the microstructure deriving from such extreme processing conditions are coarse, with trapped porosity and hence with poor oxidation and mechanical performances. The addition of specific sintering additives has the twofold effect of decreasing the sintering temperatures down to 1650°C, and of notably modifying the performances at high temperature. This work aims to the development of ablation resistant UHTC coatings for the protection of future reusable space vehicles that should survive harsh earth and/or planetary re-entry conditions. For this purpose, selected UHTC compositions on the basis of ZrB2 (i.e. ZrB2-5WC-3SiC and ZrB2-15MoSi2) have been deposited by means of a new Shrouded Plasma Spray (SPS) technique under atmospheric conditions. A preliminary stage of the work consisted on the development of feedstock powders suitable for thermal spray processing, thus the morphology and size distribution of the powder particles were optimized to reach a good flowability and optimal processing conditions with the SPS system. Relevant SPS process parameters have been optimized based on the resulting coating microstructure and composition. Collected results led to the conclusion that the developed coatings are essentially composed of ZrB2 as main phase, indicating the low decomposition of the different feedstock powders in the plasma plume. Coatings have been applied on different type of Ceramic Matrix Composites (CMCs) (i.e. C-C, C/C-SiC) with dense structures, good adhesion to CMC base material and apparently good thermo-cycling resistance. Moreover, preliminary ablation and high temperature cycling tests have demonstrated the potentiality of the developed UHTC coatings to successfully withstand extreme thermal shock conditions without peel-off (critical delamination failure). Acknowledgements.This work has received funding from the EU FP7 Project “Super Light-Weight Thermal Protection System For Space Application" (LIGHT-TPS) under Grant Agreement no. 607182
Authors : I. Neshpor -1,O. Grigoriev-1, M. Parco- 2, I. Fagoaga- 2, L. Silvestroni -3
Affiliations : 1-Frantsevich Institute for Problems of Materials Sciences of NASU, Kyiv, Ukraine 2-Tecnalia, San-Sebastian, Spain 3-CNR, Faenza, Italy
Resume : ZrB2- MoSi2 composite powders have been obtained by carbo-thermal synthesis on a specially designed equipment and coatings were applied on C/C substrates by shrouded plasma spray method. The regimes of deposition and the optimal powders size have been determined. Some mechanical properties were measured by indentation method (hardness, fracture toughness, tension strength, compression strength, as well as microstructural (grain-boundary) strength).It was shown that the coating has relatively high hardness values, which are typically characteristic of zirconium boride ceramics. Herewith, a transition layer between the carbon and the coating has lower hardness values and it can be associated with its complex composition. The absence of differences in the length of the cracks from the corners of the prints propagating along the interfaces between the various layers and perpendicular to them indicates that the resistance to cracks propagation along and perpendicular to the interfaces for the investigated layers and interfaces is isotropic. It points out that the strength of the interfaces is the same as that of the materials adjacent to these boundaries and the absence of significant internal stresses or their relaxation. It testifies the stability and availability of such coatings application. The applied coatings were subjected to ablative testing with HHO flame.It has been determined that the coating increses the resistance of C/C composite to ablation.Acknowledgements.This work has received funding from the EU FP7 Project “Super Light-Weight Thermal Protection System For Space Application" (LIGHT-TPS) under Grant Agreement no. 607182
Authors : I. Neshpor (1), O. Grigoriev (1), V. Vinokurov (1) , L. Melakh (1), M. Parco (2), I. Fagoaga (2), , L. Silvestroni (3)
Affiliations : 1-Frantsevich Institute for Problems of Materials Sciences of NASU, 2-Tecnalia, San-Sebastian, Spain 3- CNR, Faenza, Italy
Resume : ZrB2- based dense ceramics with different sintering agents were obtained by the hot pressing and vacuum hot pressing modes. The principles of UHTCs structure and properties formation have been developed. It was determined that structure formation at sintering and shrinkage kinetics are determined by the formation of diffusion zones in the interface. In these areas the processes of phase transformations which determine the adhesion take place. Adhesive characteristics determine microstructure (grain-boundary) strength which was identified by us by the indentation method for the first time. This grain-boundary strength determines mechanical and service properties and correlation dependences of microstructure strength on other mechanical properties (fracture toughness, tension strength, compression strength) allow to create materials with necessary properties. The dense ceramics were subjected to oxidation at 1550 and at 1650°C for 15 minutes and repeated 1-3 times in a bottom-loading furnace. It revealed that method of obtaining influences oxidation resistance of the ceramics. Herewith, ceramics obtained by vacuum hot pressing showed higher resistance to oxidation compared to the other ceramics obtained by hot pressing, retaining the pristine ZrB2 under a thin outermost SiO2 glassy layer. Among the investigated materials, none showed oxide spallation and the best results were achieved when ZrB2 was sintered with solely MoSi2 or simultaneous addition of MoSi2 and CrB2. Acknowledgements.This work has received funding from the EU FP7 Project “Super Light-Weight Thermal Protection System For Space Application" (LIGHT-TPS) under Grant Agreement no. 607182
Authors : I.Gusarova-1, A.Potapov-1, p.Loboda-2, T.Manko-2
Affiliations : 1- SDO Yuzhnoye; 2-NTUU Kyiv Politecnic Institute
Resume : Scientists of all world space powers are currently engaged in creation of reusable spacecraft, providing a significant reduction of launch costs. One of the main problems in their development and operation are extremely high temperatures, which affect the surface for a sufficiently long period of time when flying with hypersonic speeds in the Earth's atmosphere. With traditional expendable launch vehicles, this task is solved by using of ablative coatings, but for reusable spacecraft different approaches and materials in the construction design should be applied. Along with the functional properties of the materials it should be taken into account their mass parameters which is the main criterion during their final selection. The objective of this work is selection of ceramic materials for the construction of hypersonic spacecraft, operating temperatures of which are up to 1200˚ C for 500 launches. The major drawback, limiting the use of ceramic materials, is their brittleness due to the presence of structural defects, which are compounded at each process step of ceramic manufacturing. Reinforcement of ceramic materials can increase their crack resistance. New promising class of materials - UHT ceramic has a very high melting point (about 3500 K), thermal stability, good thermomechanical and thermochemical properties and high oxidation resistance in the atmosphere reentry conditions, but it has sufficiently high specific mass - 4000-6500 kg / m3, therefore its application is effective at temperatures of 1500 - 1800˚ C. For structures, operating at temperatures up to 1200˚ C, it is expedient to use ceramic materials with appropriate working temperature range and lower density (2.5-3.5 g / cm3). Such a heat-resistant material for the RSC structures was developed by experts of the Kiev Polytechnic Institute and Yuzhnoye State Design Office. This is the ceramic, based on refractory boride and boron carbide reinforced with ceramic fibers. It was developed a heat-resistant structures manufacturing technology of such materials based on fundamentally new method of growing crystals of refractory compounds with non-crucible zone melting, created at Kiev Polytechnic Institute.
Authors : V.P. Solntsev; V.V. Skorokhod; G.A. Frolov; K.N.Petrash; T.A. Solntseva; A.M. Potapov; I.A. Gusarova
Affiliations : V.P. Solntsev; V.V. Skorokhod; G.A. Frolov; K.N.Petrash; T.A. Solntseva - Frantsevich Institute for Problems of Materials Science NAS of Ukraine A.M. Potapov; I.A. Gusarova - Yuzhnoye State Design Office named after M. Yangel
Resume : It was first when the ideas of thermodynamics of irreversible processes in the reaction sintering of powder metal alloys were put into practice. During sintering of metal alloys non-equilibrium reaction processes lead to the complete elimination of inheritance of structural defects inherent in the powder material. Thus the material improves its physicomechanical and technological properties. The theoretical research results of nonequilibrium topochemical reactions at high temperature oxidation deliberately allowed choosing the composition of the alloy which formed a stable protective film on its surface. All this is implemented in the development of a new generation of heat resistant alloys stable under cyclic stressing. Thus a new heat-resistant dispersion-hardened alloy based on niobium with reduced density of 5.558 g / cm3 was developed and it is much lighter than metal alloys used for thermal protection of reusable space systems. Technology of reaction sintering of the material based on niobium was implemented. The heat resistance of the alloy has been investigated. It has been established that the material is suitable for operation under temperature cycling to 1200 0C, as it withstood 100 cycles of heating and cooling to room temperature. The test material has lost only 11% of its mass over the full test period.
Functional composites for various applications : Prof. IRYNA UVAROVA
Authors : L.Vyshniakov-1, Yu.Vasilenkov-1, I.Bilan-1, C.Charitidis-2, I.Gusarova-3
Affiliations : 1-Frantsevich Institute for Problems of Materials Sciences of NASU, Kyiv, Ukraine; 2-National Technical University of Athens, Athens, Greece; 3-SDO Yuzhnoye, Dnipro, Ukraine
Resume : Textile fabrics on the base of carbon fibers and yarns may be used for protection from electromagnetic radiation. Carbon fibers and yarns for such fabrics are usually produced from viscose yarns by means of their chemical and thermal treatment. In this case viscose yarns are subjected to the processes of pyrolysis and carbonization. Yarns from such carbon fibers have the low elastic modulus so they may be treated on knitting machines with production of various combine interweaving. Such fabrics are characterized by enhanced elasticity and volumability. Knitting structures are very promising for creation of shielding fabrics (protection from electromagnetic radiation) because volume structure of knitted fabrics allows to realize physical effects promoting multiple reflection and absorption of electromagnetic waves. Furthermore knitting technology allows to use another kinds of fibers including cotton, metal, synthetic together with carbon ones for production of combine textiles. It allows to create a complex of required functionalities combining high mechanical properties (elastic modulus and strength) with shielding ability and tribotechnical characteristics (in corresponding composites) and other service properties in combined textile structures. Within the framework of FIBRALSPEC project activity weft-knitted combine fabrics consisting from straight high modulus carbon fibers from PAN fibers and ground fibers from low modulus carbon fibers from viscose fibers had been developed. In such kind of materials it is possible to combine fabric high strength due to weft yarn and fabric volumability created by ground yarns. For the enhancing of the bulk properties textured (bulk) yarn produced by the original technology of viscose directed shrinkage including knitting of viscose fabric, its thermal treatment with the following fabric untangling into carbon yarn. The technology of production of textured carbon fiber with given degree of volumability had been described. The examples of its application for weft-knitted and woven fabrics had been presented. Also the materials structure and properties (carbon fibers and fabrics) had been presented too. The results of mechanical and shielding tests for combined textiles and their dependencies from the composition and structure of fabrics had been described. On the base of obtained results some recommendations concerning industrial possibilities for weft-knitted and woven fabrics containing carbon fibers and yarns had been made. Acknowledgements This work has received funding from the EU FP7 Project “Functionalized Innovative Carbon Fibres Developed from Novel Precursors with Cost Efficiency and Tailored Properties” (FIBRALSPEC) under Grant Agreement no. 604248
Authors : Anna Tondos, W?odzimierz Bogdanowicz, Jacek Krawczyk
Affiliations : University of Silesia, Institute of Materials Science, Department of Crystalography 75 Pulku Piechoty 1a street 41-500 Chorzów
Resume : Structural defects of as-cast single-crystalline CMSX-4 turbine blades were studied. Nickel-based CMSX-4 composite material consist mainly of two phases: one phase - forming the matrix and another one - which occurs in reinforcement. The blades were obtained by the Bridgman technique and cut along withdrawal direction. Longitudinal microsections were examined by X-ray diffraction methods complemented by Scanning Electron Microscopy (SEM). Back reflection Laue method and scan diffraction mapping were used to crystal orientation studies. X-ray topography of Auleytner projection technique with divergent beam was used. The dendrites array were visualized by macro-SEM images. It was stated, that many structural defects, such as local crystal misorientation and local internal stresses formed during growth process, have their origin near the walls of the mould. The defects areas spread out from the mould surface over the interior of the blades, perpendicular to the crystallization direction. It was observed that the defects are created in the area where the dendrite cores propagation is confined by the mould walls. Those effects occur more frequently in the places where the lateral cast section changes and mould surface is uneven.
Authors : Nachum Frage, Shmuel Hayun,
Affiliations : Ben Gurion University of the Negev
Resume : Recently the advanced ceramic group in Ben-Gurion university of the Negev, Israel reported on new family of low temperature reaction bonded boron carbide composites. It was demonstrated that fully dense B4C-Mg, B4C-AZ91 alloy, B4C-Mg,Si (eutectic) and B4C- Al alloys composites can be fabricated at a significantly lower (750–1000 °C) temperature range. The key feature of the novel approach is based on the Mg-vapor atmosphere, under which the infiltration process is carried out. The microstructure and the mechanical properties of the composites will be described and discussed. It was concluded that the formation of the deleterious aluminum carbide (Al4C3) depends on the presence of free carbon in the boron carbide powders. In The present talk is concerned with the latest advancements in the fields of reaction-bonded boron carbide.
Authors : Y.V.Naidich, B.D.Kostyuk, T.V.Stetsyuk
Affiliations : Frantsevich Institute for Problems of Materials Science of NASU, 3 Krzhyzhanovsky Str., Kiev, 03142, Ukraine,
Resume : In the implementation of the concept of high-power (2,5 kW) electron-beam welding tool of new generation for fitting and repair works in space technological process has developed, This process allows in one vacuum-thermal cycle to receive complex electronic unit which has necessary strength, vacuum tightness, working temperature, resistant to thermal cycling and electrical breakdown. Working properties of the samples of location ceramic-metal assemblies of high-voltage cathode block were tested and has been received following data: bending strength ? ~ 200 MPa; operating temperature from 500 ? 700 °C up to 750 °C; vacuum tightness was determined by the method of pressure testing, but at high pressure up to 4-5 atm joints vacuum tightness was fully preserved; resistance to thermal cycling by regime 500 ? 20 ? 500 °C in vacuum and in air after 30-50 cycles vacuum tightness and strength are fully preserved. High-voltage insulator of electron-beam emitter which has been made from three metal units (high-voltage insulator, pin, cathode unit) was tested by the following parameters: a) vacuum tightness; b) high-voltage tests between metal electrodes (covar and stainless steel). Vacuum tightness test showed that all welded- brazed joints have allowed reach and save vacuum up to 1 x 10-7 torr (1 x 10-5 torr is sufficient). High-voltage tests showed that at voltage of 5 kV (more than 2 times exceed allowable voltage) electrical breakdown was not observed. Electrical resistance tests showed that resistance between electrodes was from1 up to 1,5 GOm when allowable resistance is 0,5 GOm.
Polymer based composites : Prof. M.SZAFRAN
Authors : Davide Morselli; Athanassia Athanassiou; Despina Fragouli
Affiliations : Smart Materials Group, Istituto Italiano di Tecnologia
Resume : Herein, we present the formation of PMMA/ZnO porous nanocomposites by in situ synthesis of ZnO nanoparticles (NPs), either by pulsed laser light irradiation or by thermal treatment of polymeric films mixed with zinc acetate as NPs precursor. The laser irradiation was used to obtain space-selective nanocomposite formation, offering the possibility to grow NPs in a desired area of the polymeric film. Interestingly, the laser irradiation also changes the morphology of the film leading to the formation of a porous structure homogeneously decorated with ZnO NPs, in only one single step. Alternatively, a thermal treatment was used to induce the homogeneous formation of ZnO NPs on the surface and in the whole volume of PMMA electrospun micro-fibres. In this two-step process, the first step is focused on the formation of the PMMA/zinc acetate fibres by electrospinning and the second step deals with the in situ synthesis of the NPs by thermal treatment, resulting in PMMA fibres homogeneously decorated with ZnO NPs. The obtained nanocomposites show multifunctional properties such as high thermal stability, gas absorption, UV-light switchable hydrophobicity and antibacterial activity. The present findings demonstrate the versatility of using the in situ synthesis approach for preparing nanocomposites characterized by crystalline NPs homogeneously dispersed in high surface area polymeric matrices, opening the possibility to extend their use in diverse applications.
Authors : L.Vyshniakov-1, L.Pereselentseva-1, E.Vyshnyakova-1, I.Bilan-1, S.Ponomarev-1. A.Tagliaferro-2, P.Jagadale-2, I.Cannavaro-2
Affiliations : 1-Frantsevich Institute for Problems of Materials Sciences of NASU, Kyiv, Ukraine;2-Politecnico di Torino, Torino,Italy
Resume : Nanostructured amorphous spherical carbon particles and graphite like flat ones had been synthesized from pine chips by the methods of hydrothermal treatment and catalytic carbonization. Characterization of the particles had been made by FTIR, XRD, SEM, TEM, RAMAN methods. . Produced particles had been used for modification of epoxy binder in carbon plastics containing high modulus carbon fibers. Carbon particles had been introduced into binder in amounts 0,2-0,7 w.% by means of their trituration in less viscous binder component with the following ultrasonic dispersion .Modified binder had been combined with CF on the special laboratory stand and as a result the samples of microplastics had been produced. Such microplastics had been tested by means of SEM (surface microstracture). Furthermore their tensile strength has been studied. The results of tests showed that introduction of nanostructured carbon graphite like flat particles into binder results to enhancing of carbon plastic tensile strength up up 30 %. Using of amorphous particles for the binder nanomodification left the tensile strength of microplastic unchanged but at the same time microplastic plasticity had been increased in essential manner, increasing of relative deformation was equal about 50 %. Acknowledgements.This work has received funding from the EU FP7 Project “Functionalized Innovative Carbon Fibres Developed from Novel Precursors with Cost Efficiency and Tailored Properties” (FIBRALSPEC) under Grant Agreement no. 604248
Authors : Chao Sun, Jie Zhang, Nan Zhang, Zuo-Guang Ye
Affiliations : Chao Sun, Jie Zhang, Nan Zhang, Zuo-Guang Ye, Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, Xi’an Jiaotong University, Xi’an 710049, China; Zuo-Guang Ye, Department of Chemistry and 4D LABS, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
Resume : The interphase between fiber and matrix plays an essential role in the performance of composites. Herein, we presented an effective method on the base of atomic layer deposition (ALD) process to modify the glass fiber and eventually fabricated multifunctional glass fiber/polymer composites. The enhanced interphase between glass fiber and epoxy was modified by depositing few tens nanometers ZnO nano-layer onto the surfaces of glass fibers via ALD at 200 ℃. Through a common fragmentation test, we found that the interfacial adhesion strength of single fiber composite was drastically increased. And with the increase of ZnO thickness, a critical thickness of ZnO of about 47 nm leads to the maximum interfacial strength which is more than 250% increase from the control fiber. Additionally, the fiber is functionalized by the ZnO nano coating since a conductive path was formed on the surface of the fiber and the UV sensing property was introduced to the fiber due to the photoconductive effect of ZnO. Consequently, introducing nanoscale semi-conductive oxide into fiber reinforced composite via ALD process can enhance the interfacial strength, and fuctionalize the composite.
Authors : Vahid Tahouneh
Affiliations : Young Researchers and Elite Club, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran.
Resume : In the present work, by considering the agglomeration effect of single-walled carbon nanotubes, free vibration characteristics of functionally graded (FG) nanocomposite sandwich curved panels resting on Pasternak foundation are presented based on the three dimensional elasticity theory. Through using a two-parameter micromechanical model of agglomeration, the vibration analysis of thick laminated panels with functionally graded nanocomposite sheets is carried out. The volume fractions of randomly oriented agglomerated single-walled carbon nanotubes (SWCNTs) are assumed to be graded in the thickness direction. An embedded CNT in a polymer matrix and its surrounding inter-phase is replaced with an equivalent fiber for predicting the mechanical properties of the carbon nanotube/polymer composite. To determine the effect of CNT agglomeration on the elastic properties of CNT-reinforced composites, a two-parameter micromechanical model of agglomeration is employed. In this research work, an equivalent continuum model based on the Eshelby-Mori-Tanaka approach is employed to estimate the effective constitutive law of the elastic isotropic medium (matrix) with oriented straight CNTs. Because of using two-dimensional generalized differential quadrature method, the present approach makes possible vibration analysis of cylindrical panels with two opposite axial edges simply supported and arbitrary boundary conditions including Free, Simply supported and Clamped at the curved edges. The convergence of the method is demonstrated and comparisons are made between the present results and results reported by well-known references; and have confirmed accuracy and efficiency of the present approach. The benefit of using the considered power-law distribution is to illustrate and present useful results arising from symmetric and asymmetric material profiles. The effects of two-parameter elastic foundation modulus, geometrical and material parameters together with the boundary conditions on the frequency parameters of the laminated FG nanocomposite panels are investigated. It is shown that the natural frequencies of structure are seriously affected by the influence of CNTs agglomeration. This study also serves as a benchmark for assessing the validity of numerical methods or two-dimensional theories used to analysis of laminated structures.
Authors : Myshak V., Seminog V., Dmytrieva T., Bortnitsky V.
Affiliations : Institute of Macromolecular Chemistry NAS of Ukraine, 48, Kharkivske shosse, Kyiv, 02160, Ukraine firstname.lastname@example.org , email@example.com
Resume : Pyrolysis mass-spectrometry (PMS) has been employed to investigate a process of thermal destruction of the secondary polyethylene (SPE), which was modified using hexamethylenetetramine (HMTA). The introduction of powdered HMTA in the polymer matrix on the basis of SPE, with a view to its mechano-chemical modification, leads to structural changes in the polymer matrix, to the formation of cross chemical bonds between macromolecules in SPE, with the participation of the ionic fragments of the collapse of HMTA, and to high content of gel-fraction of compositions, with increasing of content of HMTA in them. Оn the basis of the results, which were obtained by PMS and by measuring the content of gel-fraction of compositions on the basis of SPE, which are modified by HMTA, it was found that mechano-chemical modification of SPE using chemically-active component - HMTA, in the studied range of concentrations, accompanies by its decay into chemically active ion-fragments. This ion-fragments are extremely reactive and can react with polyethylene as with the matrix and with functional groups on the surface of the SPE with the formation of different composition of structural fragments. As a result of such processes the crosslinked structures form in the phase of the modified polymer, and affect the thermal and physico-mechanical properties of the compositions. The obtained results can serve as a basis of technological process of obtaining of composite material using secondary polyethylene as polymer matrix.
Fiber reinforced composites (some results of FP7 FIBRALSPEC project) : Dr. IRYNA BILAN
Authors : Katalin Balazsi-1, Orsolya Tapaszto-1, Zsolt Fogarassy-1, Jan Dusza-2, Andreas Kailer-3, Csaba Balazsi-1
Affiliations : 1- Thin Film Physics Department, Institute for Technical Physics and Materials Science, Centre for Energy Research, Budapest, Hungary; 2-Institute of Materials Research, Slovak Academy of Sciences, Kosice, Slovakia 3-Fraunhofer-Gesellschaft Institute for Mechanics of Materials IWM, Freiburg, Germany
Resume : Silicon nitride is a promising structural ceramic material that was developed in a search for high strength and high toughness ceramics that could replace metals in advanced turbine and reciprocating engines to give higher operating temperatures and efficiencies. During the last few years new cost effective, high quality carbon based filamentous was developed in the form of graphene platelets (GPLs), also called graphene nanoplatelets (GNP), multilayer graphene nanosheets (MGN) or graphene nanosheets (GNS). These platelets demonstrate exceptional high thermal and electrical conductivity and an exceptional combination of mechanical properties. The aim of the present work is to investigate the influence of the addition of various kinds of graphene nanoplatelets on the structure and other properties of Si3N4 based composites prepared by high efficient attritor milling and sintered by spark plasma sintering. Acknowledgement Authors thanks to M-ERANET "Grace" Graphene-ceramics composits for tribological application in aqueous environments.
Authors : Ho-Sung Yang, Woong-Ryeol Yu
Affiliations : Department of Materials Science and Engineering and Research Institute of Advanced Materials (RIAM), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-744, Korea
Resume : Wet spinning process is a common technique for manufacturing fibers from polymer solutions. Poly(acrylonitrile) (PAN) fibers, precursors of carbon fibers, are manufactured via wet spinning process because the decomposition of PAN occurs at temperature lower than its melting point. Many researches have been conducted focusing on wet spinning of PAN since 1980s as consumption of carbon fiber for advanced fiber composites has significantly increased due to its strong mechanical properties. Most of them, however, are related to additives in PAN and control of spinning parameters: solution concentration, flow rate, coagulation solvent composition, draw ratio, etc. In this study, we introduce a new parameter, electrical current, to wet spinning process and systematically investigate its effect on the mechanical properties of wet-spun PAN fibers. First, wet spinning facilities were prepared in lab scale, following literature The electrical current was imposed into PAN solution before PAN comes into contact with coagulation solvent. The mechanical properties of PAN fibers manufactured through electrical current-assisted wet spinning process were characterized and compared with PAN fibers manufactured from normal wet spinning process. Finally, the microstructural analysis was performed to investigate the effect of electrical current on the microstructure of PAN fibers and further their mechanical properties.
Authors : L.Vyshniakov-1, L.Pereselentseva-1, E.Vyshnyakova-1, I.Bilan-1, S.Ponomarev-1. A.Tagliaferro-2, P.Jagadale-2, I.Cannavaro-2
Affiliations : 1-Frantsevich Institute for Problems of Materials Sciences of NASU, Kyiv, Ukraine; 2-Politecnico di Torino, Torino,Italy
Resume : Carbon fibers, textured carbon yarns and various combined fabrics containing CF are the most promising reinforcement material for polymer based composites with different functionalities. It is known that the surface of carbon fibers (CF) produced from organic polymer precursors is characterized by the presence of defects in the kind of grooves and cracks. For the smoothing of the CF relief and increasing of adhesive strength on the boundary fiber- polymer binder usually it is proposed to use the coatings (glazing). Usually organic polymers (polyvinyl alcohol, epoxy resins), inorganic compounds carbon are used for such coatings. It is proposed to use for CF glazing graphene aqueous solution, produced by the authors by means of extraction from carbonized wood wastes (pine chips). Characterization of graphene coatings had been made by the methods of X-ray diffraction, electronic microscopy, thermal analysis, Raman spectroscopy. Investigations had been made for commercial fibers УКН-5000 (Russian Federation). Various kinds of preliminary treatments (hot water, chemical treatment by acids, oxidation heating) had been used for the commercial glazing deleting. Graphene coatings had been deposited by means of pulling of treated CF through graphene aqueous solution with the following drying at the temperatures not less than 200 С. The influence of graphene coatings on the strength of CF had been studied by the method of CF monofilament stretching. It was established that graphene coatings created on УКН-5000 fibers increase their strength up to 20 % in dependence of the kind of preliminary treatment. Acknowledgements.This work has received funding from the EU FP7 Project “Functionalized Innovative Carbon Fibres Developed from Novel Precursors with Cost Efficiency and Tailored Properties” (FIBRALSPEC) under Grant Agreement no. 604248
Authors : Dirk Schmelter-1, Arthur Langry -2, André Koenig-1, Patrick Keil-1, Fabrice Leroux- 2, Horst Hintze-Bruening-1
Affiliations : 1- BASF Coatings Division, Muenster, Germany; 2- Institute for Chemistry of Clermont-Ferrand, France
Resume : Layered double hydroxides (LDH) have been proposed as positively charged layered nano fillers for polymer composites. However to obtain polymer intercalation and optional platelets exfoliation counter ion issues limit their use for aqueous colloidal formulations comprising anionic stabilized polymers, usually used for organic coatings. To overcome this cutback acetate has been proposed as pristine counter ion, able to form volatile ammonium acetate in conjunction with the polymer counter cation. Furthermore metal acetates are convenient precursors for in-situ LDH and layered single hydroxide (LSH) synthesis in the presence of the polymer. In that context we recently have introduced the beneficial use of novel anionic bola-amphiphilic compounds for layered hydroxide hybrid formation, especially for LSH, a novelty in that domain. This report will focus on ex-situ LDH-acetate processing making use of these bola-amphiphiles as a formulation base for LDH based polymer composites. Comprehensive analysis for acetate and bola species along the processing steps, accompanied with real-time (SAXS) structural characterization of intermediates as well as of final coatings (SAXS, XRD, TEM) give insights into intercalation scenarios that depend on stoichiometry, bola composition and the polarity of the medium. The implications on mechanical (DMA) and barrier (oxygen permeability) film properties as well as on their corrosion inhibition properties on steel, studied with scanning Kelvin probe (SKP) are discussed.
Authors : A. Mednikova, V. Rumyantsev, R. Sapronov
Affiliations : Virial LTD, Saint-Peterburg,Russia
Resume : The subject of the present research wasСf/SiC compositedeveloped at Virial LTD.Processing of Сf/SiCwas based on Si melt infiltration of the C/C preforms obtained via carbonization of carbon-fiber reinforced plastic (CFRP) preforms. CFRP preforms were formed via direct filament winding of carbon fibers infiltrated with LBS-1 resin 1 (loaded with SiC particles with grit sizes М40 and М7), subsequently cured in air, heat-treated under protective gas, machined and post-densified with additional resin infiltration.SiC matrix was formed via chemical reaction between silicon melt and coke within the preform. The processed Сf/SiC-composites were characterized for density, open porosity and Si volume fraction, with the average values being 1.85 g/cm3,0.95 % and 6 vol.%, respectively. Fig. 1 (a, b) shows the general view of the final CMC-parts, and Fig. 1 (с) shows the virtually pore-free cross-section of the sample. All filaments feature carbide phase contour and traces of residual Si. Carbide phase was also discovered inside fiber tows. The tribotechnical components based on Сf/SiC-composites may be used in wear-resistant friction units operating under heavy loads, e.g. in the next-gen submersible oil pumps. Such composites may also be processed into larger-size parts with increased impact resistance.
Poster Session : Prof. IRYNA UVAROVA
Authors : T. Stetsyuk-1, V. Malyshev-2, D. Shakhnin-2, N. Uskova-2, M. Gaune-Escard-3
Affiliations : 1-Frantsevich Institute for Problems of Materials Science of NASU, Kiev, Ukraine; 2-Vernadsky Institute of General and Inorganic Chemistry of NASU, Kyiv, Ukraine; 3-Aix-Marseille University, Ecole Polytechnique, IUSTI, CNRS, Marseille , FRANCE
Resume : Molybdenum (tungsten)?nickel (cobalt) alloys and intermetallics can be deposited as continuous layers on a cathode from oxide tungstate melts. The composition and structure of the deposits can be controlled by varying the concentration of the corresponding components in the melt, the temperature, and the cathodic current density. An increase in the nickel (cobalt) content in an alloy with an increase in its concentration in the melt, a decrease in the cathodic current density, or an increase in the electrolysis temperature are most likely due to an increase in the fraction of the total current consumed to deposit nickel (cobalt) and to a decrease in the diffusion retardation for the ions of the more electrochemically negative component of the alloy.
Authors : T. Stesyuk-1, V. Malyshev-3, A. Gab-2, A. Pisanenko-3, M. Gaune-Escard-4
Affiliations : 1-Frantsevich Institute for Problems of Materials Science of NASU, Kiev, Ukraine; 2-Vernadsky Institute of General and Inorganic Chemistry of NASU, Kyiv, Ukraine; 3-National Technical University of Ukraine "Kyiv Polytechnical Institute", Kyiv, Ukraine; 4-Aix-Marseille University, Ecole Polytechnique, IUSTI, CNRS, Marseille , FRANCE
Resume : The systems suitable for a high-temperature electrochemical synthesis on the surfaces of diamond, boron nitride, and silicon and boron carbides were selected on the basis of the thermodynamic analysis of the reactions of dielectrics and semiconductors with ionic melts and the study of their electrochemical behavior. Electroplating of the grains of dielectrics and semiconductors with molybdenum carbide favors the increase in their breaking load and wettability and in the efficiency of tools. Thermodynamic calculations showed that the most energy favorable process for boron nitride is its oxidation to gaseous nitrogen and boron metaborate or oxide. A compound of an element of group VI and carbon will be presumably reduced to this element in the pure state or to its oxide of an intermediate oxidation state. The most energy favorable process for silicon and boron carbides will be their oxidation to a metasilicate (metaborate) or silicon (boron) oxide. A compound of an element of group VI will be also presumably reduced to the elements in the pure state or in the form of an intermediate oxide.
Authors : Sydorenko Tetiana.
Affiliations : I. Frantsevich Institute of Problems of Materials Science of NAS of Ukraine
Resume : Wettability processes are among the main factors in brazing and soldering procedure. High wettability of materials to be joined by brazing filler alloys determines both the process of joint formation and its high adhesion strength. In this work, the wetting and contact interaction of perovskite PNZT–ceramics with Ag-Pb melts were investigated in air. Dependence of contact angle Ag-Pb-O melts on perovskite ceramics in air at concentration of Pb and kinetics of wetting processes were studied. It was shown that contact angle for a pure Ag on PNZT ceramic substrate is 92 degrees, and it decreases up to 33 degrees if Pb concentration increases up to 5 at. %. Analysis of the perovskite ceramics/Ag-Pb-O alloy interface shows the presence of a transitive zone ~2 μm thick. The microstructure of the transition layers at the contact interface ceramic-to-metal was investigated and analyzed using thermodynamic calculations.
Authors : Durov O.V., Sydorenko T.V.
Affiliations : I. Frantsevich Institute of Problems of Materials Science of NAS of Ukraine
Resume : Influence of an electric current passing through the interface on wetting of some ceramic materials (zirconia, hafnium dioxide, barium titanate, et al.) was investigated in out early works. In this work the electrowetting of semiconducting tin dioxside by Ag-Cu melts was studied at 1270 K in air media. It was shown that after heating and electric current passing through the ceramics-metal interface (~ 30 min) the contact angle of Ag-39Cu decreases in cathode, and increases in anode SnO2-substrate. The microstructures of contact zones of ceramics and metal for cathode and anode substrates were studied and analyzed.
Authors : Joanna Szymanska, Pawel Wisniewski, Dorota Zarzycka, Jaroslaw Mizera, Krzysztof Jan Kurzydlowski
Affiliations : Warsaw University of Technology; Faculty of Material Science and Engineering; Woloska 141 Street; 02-507 Warsaw
Resume : Shale gas extraction is going to become one of the most prospective solution for the oil&gas industry in the near future. The current and most practiced stimulation of unconventional gas reservoirs is hydraulic fracturing. This treatment is based on pumping a hydraulic fluid into the horizontal wellbore (up to 5000-7000 meters deep) at a high pressure to a value greater than the breakdown pressure of the formation and thus creation of conductive for shale gas fractures. The fracturing fluid properties strictly determine the creation and propagation of the fracture. The fluid viscosity is an essential rheological property that has impact on the net pressure, the near-wellbore drop and the pressure drop resulting from tortuosity between the wellbore and the propagating fracture. Moreover, quality of the fracturing fluid is a measure of proper high proppants concentrations transport, inhibition of microorganism growth, compatibility with the rock and pipes in the borehole, minimum friction pressures losses during injection, proper density (affects the surface injection pressure and the ability of the fluid to flow back after the treatment), controlled pH and formation-compatiblity ensuring low production costs. The fracturing fluid is mainly composed of water (90%) but also includes a variety of chemical additives (~1%) depending on the fractured reservoir (shales geology, well pressure and temperature) - each component serves a specific purpose. Remaining part (9-10%) accounts for the proppants – composites in a form of granules settled in the induced fractures (the rock closure prevention). The aim of the research was to verify improved ceramic proppants suspension in the fracturing fluid through the proper dynamic viscosity determination. Experimental studies concerned methylcellulose addition to the water sample at various concentrations. This commonly used organic constituent (polymer) induces gel formation by secondary crosslinking in the flowback but ensures low initial dynamic viscosity and stability in the proppants transport inside the rock (sedimentation avoidance). The outcomes indicate a significant impact on the rheological fluid properties (Zahn cup viscosity, dynamic viscosity), its density and pH in relation to the variable methylcellulose content (~1%) and thus prediction of the fluid behavior under mining conditions. It is also a basis for the further fracturing fluids modifications taking into account other groups of chemical additives.
Authors : Tolochyna O.V., Bagliuk G.A., Tolochyn O.I., Yakovenko R.V.
Affiliations : Frantsevich Institute for Problems of Materials Science of National Academy of Sciences of Ukraine
Resume : We have studied the synthesis of intermetallic Fe-16 mass% Al of powders metals and compression it by hot forging. From a mixture of aluminum and iron powders at compression by hot forging at temperatures of 950 ° C, 1050 ° C and 1150 ° C was obtained a material, which consists of several phases Fe2Al5, FeAl, Fe3Al, and which has such properties: electrical resistivity 80-140uOhm*cm, density – 6,2 – 6,5 g/cm^3 and bending strength 500 – 420 MPa. After annealing the material at 1300 ° C and holding 2 hour is obtained a single-phase material which consists of a Fe3Al phase. On the samples were studied the structure and the complex physical and mechanical properties: electrical resistivity 130 – 140 uOhm*cm, density – 6,2 – 6,5 g/cm^3 and bending strength 1300 – 1100 MPa. Thus, we realized the possibility of intermetallic compounds by combining synthesis and compression to one stage, which allows to obtain a solid powder intermetallic Fe3Al, whose properties are not inferior to similar intermetallic compounds obtained by casting and rolling. Hence, this way of intermetallic production could be considered as resource saving technology.
Authors : Y. Kolodkevich-1, V. Tkachuk-1, A. Luchenok-1, T. Basyuk-2, T. Prikhna-2, L. Sudnik-1
Affiliations : 1 - SSSE "Research Institute of Pulse Processes with Pilot Plant", Minsk, Belarus;2- Institute for Superhard Materials, NASU, Kiev, Ukraine.
Resume : Shock wave loading is one of the promising methods of processing of materials and characterized by high temperatures and pressures. The powders of Ti2AlC and Ti3AlC2 were synthesized at the Institute of Superhard Materials by the free sintering in a vacuum at 1350°C. Synthesized powders with Ti-Al-C phases were subjected to the shock wave impact loading with using industrial low blasting explosives on the flat pattern. The parameters of shock wave loading are: detonation velocity D=4 km/s, pressure about 2.5-3.5 GPa. Two samples based on Ti2AlC and four samples based on Ti3AlC2 composition were produced. The content of the MAX phase of structural type 211 after compacting was about 96 wt.%, obtained samples have the values of porosity in the range of 17-19 %. There is a partial destruction of the 312 phase under shock-wave loading, but weight content of Ti3AlC2 phase is 78-92 wt.%. Density of the compacts was of 3.6 to 3.7 g/cm3, but these values are significantly different from the theoretically attainable density of MAX phases and indicate a relatively high level of porosity (more than 13%).
Authors : M. Nedielko-1, O. Alekseev-2, M. Lazarenko-2, K. Kovalov-2, S. Tkachov-1
Affiliations : 1-E.O. Paton Electric Welding Institute of NASU, Kyiv, Ukraine; 2-Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
Resume : Cellulose matrix, especially micro/nano composites (MNC), now are under intensive studies as their perspectives spread from ?paper electronics? and ?printing? to forensic examination and eco-friendly sorbents. At the same time there are a few data about properties of the ?MNC ? oxide? composites. In this work several sets of the composite samples, both MNC and MNC embedded with inorganic oxide dielectric (IOD) micro/nanoparticles were prepared and studied. The disks of composites were pressed from initial micro/nanosized powders of the MNC and mixture of the MNC and IOD (un-doped and doped with RE ions phosphates and vanadates). Some of the samples were undergone to carbonization via procedure of temperature treatment in the range 50 ? 2500C in ambient atmosphere. Morphology of the samples surfaces was investigated using optical and electronic microscopy. Temperature dependences of the specific capacity and dielectric losses tangent were measured in -100 ? 1000C temperature range when frequency of electric field varied from 1 to 100 kHz. As result, components of the complex dielectric permittivity, ?*, ?0 conductivity and other relaxation parameters were evaluated. Carbonization effect and a role of molecular anions of oxide components of composites have been discussed. Acknowledgement. Publications are based on the research provided by the grant support of the State Fund For Fundamental Research of Ukraine (project F64/32-2015).
Authors : P. Lada, A. Miazga, K. Konopka, M. Szafran
Affiliations : Warsaw University of Technology, Faculty of Materials Science and Engineering Woloska St. 141, 02-507 Warsaw
Resume : One of the important aspect in the preparation of composite materials is the possibility of reaction between used components. In the case of composite from ZrO2 ? Ti system, the reaction could take place between the zirconia matrix and titanium particles during the sintering process. The diffusion of titanium into zirconia has been studied in previous works in order to verify the mechanism of zirconia stabilization by addition of titanium or titanium alloys. Experiments were conducted at temperatures higher than melting point of Ti (1667°C). Nevertheless, only little research has been reported on the ZrO2/Ti interface created at a temperature lower than the melting point of titanium. In the present work the experiment with the yttria-stabilized zirconia/titanium plates sintered in argon at 1450°C were presented. .The SEM observation made on cross sections perpendicular to the interface show that the reaction between components occurred. The study of phase composition (XRD) confirmed the formation of new phase of Ti-Zr-O system. In addition, the microhardness measurement was carried out perpendicular to the diffusion layer. Keywords Zirconium oxide, titanium, composite, diffusion Acklowledgements The work was done in frame of the project financed by National Center of Science (NCN), project DEC-2013/11/B/ST8/00309.
Authors : Iurii Falchenko, Anatolii Ustinov , Lidia Petrushinets ,Tatyana Melnichenko, Irina Gysarova, Vitali Yatsenko
Affiliations : THE E.O. PATON ELECTRIC WELDING INSTITUTE OF THE NATIONAL ACADEMY OF SCIENCES OF UKRAINE
Resume : During diffusion welding of heat-resistant Ni-Cr alloys usually are applied high temperature and welding pressure, due to the presence of dense oxide film on the surface of the alloys. Because of oxide film the alloys have resistance to oxidation at high temperatures, but it complicates the welding process. The research object of this paper is obtaining of welding joints with porosity foils. Porosity foils were obtained by the technology of electron beam evaporation and condensation under vacuum. It is shown that the usage of such foils allows to activate the diffusion processes at the contact surfaces. Moreover, it allows to reduce the temperature and pressure of the welding process.Acknowledgements.This work has received funding from the EU FP7 Project “Super Light-Weight Thermal Protection System For Space Application" (LIGHT-TPS) under Grant Agreement no. 607182
Authors : P.S. Smertenkoa, O.P. Dimitrieva, D.O. Grynkoa, O.M. Fedoryaka, N.A. Ogurtsovb, A.A. Pudb, Yu.V. Noskovb,
Affiliations : a V.Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, pr. Nauki 45, Kyiv 03028, Ukraine b Institute of Bioorganic Chemistry and Petrochemistry, NAS of Ukraine, 50 Kharkivske shose, 02160, Kyiv, Ukraine
Resume : Nanostructured CdS layer/organic P3HT:PCBM or ZnPc-4R:PCBM composites were formed on the indium-tin-oxide (ITO)/glass substrate with PEDOT:PSS composite film as the top electrode . On the base of quasi-DC measurements of current-voltage characteristics (CVC) it has been found that CdS plays the role of an electron-transporting (hole-blocking) underlayer to rectify electron flow from the P3HT:PCBM bulk heterojunction to the ITO electrode. The application of investigated composite as PV cell have shown a few ways to their further optimization: (i) the thickness of CdS layer used in the above cells has to be decreased up to 100 m or even less; (ii) the surface of nanostructures CdS should be well controlled in order to provide good contact with the organic counterpart and to serve as a charge sink, respectively; (iii) the nanostructured CdS layer can work not only as a selective electrode, but also as an active component of the PV cell, for example, participating in dissociation of excitons generating in the organic layer and (iv) a clamped top contact of PEDOT:PSS has to be optimized. Solution of the above problems is believed to allow one to construct the inverted PV cells with better performance. So, the bifunctional role of the CdS nanostructured layer as a means to increase the interface with the active layer and as a bottom electrode with better electron affinity than ITO has been shown. Financial support of CRDF project No. UKE2-7035-KV-11.  D.O. Grynko, O.M. Fedoryak, P.S. Smertenko, N.A. Ogurtsov, A.A. Pud, Yu.V. Noskov, O.P. Dimitriev, Application of CdS nanostructured layer in inverted solar cells, Journal of Physics D: Applied Physics, 2013, 46, 495114.
Authors : N. Busko, A. Barantsova, V.Grichshenko, N. Gudzenko, U. Silchenko, Ya. Kochetova
Affiliations : Institute of Macromolecular Chemistry of NASU
Resume : The method of synthesis of oligomeric azoinitiator (OAICO) on the base of bifunctional monomer azoinitiator azo-bis-isobutyrohydrazone of cyclohexanone (AGN-CН) processed isophorone diisocyanate (IPDI) and of castor oil (CO) at molar ratio of AGN-CH-IPDI:CO =1:2 was developed one initiating center the OAICO 1/2 received with structure RХR, where R - is the castor oil block, and X is the initiator block. At molar ratio of AGN-CH-IPDI:CO = 2:2 the oligomeric azoinitiators OAICO 2/2 with two initiating centers was obtained with structure (RХ)n or R2Х2. Oligomeric azoinitiators have been studied by the method of IR- and UV-spectroscopy. Block copolymers of type (ABA)n (A – block of castor oil, B – block of oligostyrene) with various lengths of oligostyrene block were synthesized on the base of synthesized oligomeric azoinitiator of castor oil and styrene as monomer by the method of thermoinitiated radical polymerization. The BCPs were obtained at molar ratio OAI/St = 1/140, 1/200, 1/400 under the following conditions: at temperature 950С throughout 20 hours. In so far, as PAI formation through the reaction between the isocyanate groups of AGN-CH-IPDI and the hydroxyl groups of CO proceeds independently of the thermoinitiated polymerization of styrene, it was possible to prepare two series of polyblock BCPs of type (АBА)n (where A is the castor oil block, and B is the styrene block). The sequential one was obtained by the synthesis of PAI in the first step, and by subsequent radical polymerization of styrene thermoinitiated by PAI, while both reactions were carried out in a single step to prepare the simultaneous one. Relaxation transitions in the soft (castor oil) and hard (oligostyrene) blocks of new synthesized block-copolymers were investigated by the DSC method.
Authors : L.A. Honcharova, L.V. Karabanova
Affiliations : Institute of Macromolecular Chemistry of the NAS of Ukraine - 48 Kharkivske highway, 02160 Kiev, Ukraine E-mail: firstname.lastname@example.org
Resume : In this paper, nanocomposites based on sequential semi-interpenetrating polymer networks (semi-IPNs) consists of polyurethane (PU) and poly(hydroxypropyl-methacrylate) (PHPMA) were synthesized and investigated. 1,2-propandiolisobutyl-POSS (POSS, 1 and 10 wt%) was used as functionalized nanofiller for PU. The stoihiometric ratio [PU/POSS]/PHPMA=70/30 was in all cases. The nanocomposites were prepared by controlled swelling PU networks in HPMA and their subsequent photopolymerization with 2,2-dimethoxy-1,2-diphenylethan-1-one (IRGACURE 651, λ=340 nm). The effects induced by the POSS content (1 or 10 wt%) on the structural and thermal properties of the nanocomposites were investigated by DSC, TGA, SEM. From the DSC data the glass transition temperature (Tg) of the nanocomposites were found to increase with increasing POSS content from Tg=-61,1oC (pure PU) to Tg=-58,6oC (semi-IPN-30 with 10 wt% POSS). According to the TGA data at loadings of 1 wt% of POSS there is an observed increase in onset degradation temperature (Tonset) from 270oC for pure PU to 323oC for semi-IPN-30 nanocomposites with 10 wt% POSS. Maximum values of the thermal decomposition temperatures, defined as the second maximum of the TGA curves, shifts towards higher temperature: from 376oC for pure PU to around 387oC for all semi-IPN-30 nanocomposites. From the SEM images the homogeneous structure of the semi-IPN-30 nanocomposites becomes more segregated with increasing POSS content in the samples. We observed POSS particles aggregation in the form of rectangular microdomains at maximum POSS content. As a result the nanocomposites with more ordered structure are formed thus leading to obtain materials with improved thermal stability. The authors thank the staffs of the Center Collective Use of scientific Equipments (CCUE) NASU in IMC on research by DSC, TGA and N.G. Kholodny Institute of Botany NASU on research by SEM
Authors : V.L. Demchenko, S.V. Riabov
Affiliations : Institute of Macromolecular Chemistry, National Academy of Sciences of Ukraine, 48, Kharkiv highway, Kyiv, 02160, Ukraine. E-mail: email@example.com
Resume : For many decades, silver nanoparticles have been recognized as an antimicrobial agent and used in many fields including biomedical, food packaging, waste water treatment, etc. This explains the interest to the development of metal-polymer nanocomposites with controlled structure and properties. WAXS investigations show that transfer from pectin-P4VP IPEC (interpolyelectrolyte complexes) to pectin-Ag+-P4VP IPMC (interpolyelectrolyte-metallic complexes) is displayed on the diffractogram as a diffusion-type maximum at 2θm≈11,0о inherent to interpolyelectrolyte-metallic complexes. It is revealed that as the result of Ag+ cations reduction in IPMC bulk (with support from sodium boron-hydrate) “IPEC-Ag0 nanoparticles” nanocomposite is formed. It is shown that Ag+ reduction in IPMC under the effect of electric field takes place with formation of nanocomposite with higher metal content. By means of SAXS it is shown that relative level of structure heterogeneity grows up considerably in the following sequence: IPEC pectin-P4VP → IPMC pectin-Ag+-P4VP → nanocomposite IPEC-Ag0 (without electric field effect) → nanocomposite IPEC-Ag0 (effected with electric field). Thermomechanical analysis methods show that nanocomposite IPEC-Ag0 formed under constant electric field effect has higher glass-transition temperature Тg and relative deformation ε comparing with material received without field effect.
Authors : A.S.Manokhin, S.An.Klimenko, S.A.Klimenko
Affiliations : V. Bakul Institute for Superhard Materials 2 Avtozavodska Str, 04074, Kiev, Ukraine e-mail: firstname.lastname@example.org
Resume : One of the most effective ways to improve the performance of cutting tool is deposition of coatings on its working surfaces. It is known that cutting of hardened steels with polycrystalline cubic boron nitride (PCBN) cutting tool is characterized by high loads with contact normal and shear stresses up to 5 GPa. In such conditions the substrate-coating system should be created wich facilitates the adaptation of working surfaces to machining conditions. Materials in amorphous and amorphous-crystalline state are characterized by advanced tribological properties. The creation of coating with such structure can lead to the positive effect due to the number of reasons. First of all the one should expect the declination of the residual stresses appeared as a result of crystalline growth. The next advantage is connected with low, in comparison with PCBN, Young modulus (Е ~ 200 GPa) and thus - high plasticity of contact layer of tool. The plasticity of coating determines an active adaptation of microgeometry of surface layer of cutting tool in the initial wear period. That leads to an increase of contact area and reduction of contact stresses. As a result, the probability of micro-cracking of surface layer of tool declines. Experimental investigation of machining of hardened steel with PCBN tool with amorphous-crystalline protective coating has showed that cutting forces and average contact temperature reduce up to 20 percent, and tool life increases on 25 percent in comparison with uncoated PCBN composite.
Authors : N. Gudzenko, N. Busko, A. Barantsova, V.Grichshenko
Affiliations : Institute of Macromolecular Chemistry, National Academy of Science of Ukraine - 48, Kharkivske schausse, 02160 Kiev, Ukraine - email@example.com
Resume : The aim of this study was to develop methods of modifying the industrial alkyd resins functionalized by oligomers, and obtaining on their basis of coatings with improved physical-mechanical properties. The non-isocyanate methods synthesis of polyurethane by reaction of cyclocarbonate and primary amino- group is the most technologically through accelerated reacted at room temperature. This avoids the use of toxic isocyanates and adverse reactions during the preparation of polyurethane materials and the use is available raw materials. The oligoamidurethane were obtained in the mixture by the interaction of highly unsaturated vegetable fats with aliphatic amines and cyclocarbonate soybean oil. The reaction mixture is thermostatically with stirring at 40 ºC for 5.5 hours. Have been received modified polymeric film-forming alkyd materials with high protective properties by interaction alkyd resin (varnish PF-060) and synthesized modifier (oligoamidurethane). It is proved, that at presence in structure alkyd 5 % oligomers result in substantial increase of parameters of durability at impact, elasticity and adhesion to a metal surface.
Authors : Filipovych A.Y., Grishchenko V.K., Barantsova A.V.
Affiliations : Institute of Macromolecular Chemistry, National Academy of Sciences of Ukraine Ukraine , 02160, Kyiv, Kharkivske Shaussee, 48, E-mail:firstname.lastname@example.org
Resume : We have developed direction of the chemical modification of epoxide through introduction of urethane groups in ER without usage of toxic isocyanates. The using of cyclocarbonate oligomers (CCO) in the reaction with aliphatic amines leads to the formation of hydroxyurethanes. It is established regularities of the formation of polymers based on amine curing epoxy-cyclocarbonate compositions. High speed aminolysis of CCO determines the total curing process acceleration and the growth of system dynamic stiffness. It is established the nonmonotonic dependence of velocity and degree conversion of epoxy group (EG) and cyclocarbonate group (CG) from ratio ER: CCO. The oligomers ratio with maximum conversion rate of EG and CG is determined by some processes: aminolysis slowdown because of CG content growth, acceleration of EG conversion on account of hydroxyurethane fragment catalysis, system depletion of primary aminogroup during the initial stage of curing because of interaction with CCO. It has been considered the dynamic mechanical analysis, scan calorimetry, gel-analysis data of nonisocyanate EPU. It was shown the dependence of polymer glass transition temperature, elasticity modulus, heat endurance from ССО quantity. The modification composites based on nonisocyanate EPU have allowed to increase durability, adhesion characteristics, elasticity, energy of deformation of polymers without reduction of polymer resistance to water and heat. Modified by CCO epoxy resins, which are cured by different amines, allow to create nonisocyanate EPU with special properties (high-strength, water soluble, foam expanded materials and others).
Authors : Y. Mordekovitz, S. Hayun
Affiliations : Ben Gurion University of the Negev
Resume : Understanding the adsorption and desorption energetics of H2O molecules on surfaces is important for the development of new and more effective materials for water splitting technology. Presently, the importance of oxygen exchange materials (e.g. CeO2, perovskites) for thermochemical splitting of H2O is in focus. In the present study, the effect of different aloveal…. on the water adsorption energetics was investigated. Nanoscale doped CeO2 powders have been synthesized by a surfactant-based method. The as synthesized nano powders were found to be homogeneous solid solutions with a fluorite structure, where the lattice parameters changed with the dopants. The water adsorption enthalpy and coverage found to increases with the dopant level, which imply increasing in the surface enthalpies. XPS measurements show salute segregation farther more the presence of the salute influences the redux behavior of the cerium atom. The reasons for this behavior will be discussed.
Authors : L. Shelly, Y.Mordekovitz,S.Hayun
Affiliations : Ben-Gurion University of the Negev
Resume : CeO2 is an attractive material for various applications due to its physical, chemical and electrical properties. For example, CeO2 is a basic component in oxidative catalysis as well as sensors and fuel cell technology, where catalytically active surfaces and high ionic conductivity, well-known for CeO2, are essential. These applications are based on the easily formed oxygen vacancies in the fluorite structure of ceria due to the variable oxidation state of Ce ions (+3 and +4). Doping ceria with aliovalent cations to some extent may increase the oxygen vacancies while maintaining the cubic fluorite structure. These ceria-based materials found to have high ionic conductivity and enhance catalytically active surface. In the present work, the effect of neodymium on the formation of Ce3+ in nanoparticles ofCeO2 was investigated using X-ray photoelectron spectroscopy. The overall oxygen vacancies increased with the neodymium addition while the Ce3+ concentration was reduced. Nevertheless, the amount of OH species found at the surface increased with larger neodymium content.
Authors : I. Gab-1, A. Gab-2, N. Uskova-3, V. Malyshev-3, M. Gaune-Escard-4
Affiliations : 1-Frantsevich Institute for Problems of Materials Science of NASU,Kyiv, Ukraine; 2-National Technical University of Ukraine “Kyiv Polytechnical Institute”, Kyiv, Ukraine; 3-Vernadsky Institute of General and Inorganic Chemistry of NASU, Kyiv, Ukraine; 4-Aix-Marseille University, Ecole Polytechnique, 13453 Marseille Cedex 13, FRANCE
Resume : Based on thermodynamic calculations of possible interactions between sodium tungstate and oxygen-containing compounds of boron, carbon, phosphor, sulphur, and VI-B group metals, the probability of possible reactions was evaluated. The experimental verification of the assumptions was accomplished by the methods of potentiometry and IR-spectroscopy. The possibility of existence of (reversible) equilibrium of molten systems with the electrodes made from VI-B group metals and their carbides was proved by the electrochemical measurements and thermodynamic calculations. The conditions of electrodeposition of nanostructured tungsten coatings from these melts were found.
Authors : I.I.Gab, Y.V.Naidich, T.V.Stetsyuk, B.D.Kostyuk
Affiliations : Frantsevich Institute for Problems of Materials Sciences of NASU, Kyiv, Ukraine
Resume : Because of the aluminium coating onto some non-metallic materials, such as silicon nitride, are using for these materials brazing, it is of interest to study the aluminium nanofilm behaviour during annealing it in vacuum. In this work the changes in morphology of aluminium nanofilm 100 nm thickness were deposited onto sapphire, graphite, carbon glass, silicon carbide and silicon nitride and were annealed in vacuum of 1x10-3 Pa at temperatures up to 700 °C were investigated. It was found that the film onto all the investigated materials during annealing up to 600 °C retains its continuity. The film morphology modifications occur in the 630 – 700 °C temperature range. Nanofilm onto leycosapphire began disperse only after 10 minutes annealing at 650 °C with the dendrites formation and after 20 minutes annealing it dispersed at large fragments – islands. Aluminium nanofilm onto Si3N4 begin disintegrate at 630 °C annealing but it completely disintegrated after 20 minutes at 650 °C annealing. Dispersion beginning of aluminium nanofilm onto graphite, carbon glass and silicon carbide was detected only at 650 °C annealing and after 20 minutes exposure at this temperature it is completely dispersed. Nanofilm onto carbon glass disintegrated only after 1 hour at 650 °C annealing. In result of aluminium nanofilm onto graphite and silicon carbide at 700 °C annealing it dispersed at the separate large drops.
Authors : M.Sokol, S.Kalabukhov, V.Kasiyan, M. P. Darieland, N.Frage
Affiliations : Ben-Gurion University of the Negev
Resume : High pressure spark plasma sintering (HPSPS) was employed to fabricate polycrystalline Nd:YAG specimens with desired functional properties. Specimens fabricated under a uniaxial pressure of 300MPa at 1300°C at a heating rate of 50°C/min and holding time of 60 min displayed sub-micron microstructure and elevated mechanical properties, including resistance to thermal shock. Optical properties (i.e. spectral transmittance, fluorescence emission spectra and fluorescence lifetime)of the HPSPS-processed specimens were close to those obtained with specimens fabricated by conventional sintering procedure. Specifically, remarkable differences in threshold powerand laser slope efficiency were found and attributed to the variance inNd concentration in the specimens tested. The results of the present study indicate that the low cost and time-saving HPSPS process allows for the fabrication of polycrystalline Nd:YAG specimens with optical properties suitable for laser applications.
Authors : M. Halabi-1, A. Kohn-2, S. Hayun-1
Affiliations : 1-Ben-Gurion University of the Negev; 2-Tel Aviv University
Resume : Segregation of defects to the surfaces and interfacesof ionic materials result in the formation of a space-charge potential (SCP).SCP is studied extensively for its critical role on functional properties. Although significant theoretical advances have been achieved, the experimental evidence in nanocrystalline ionic materials is indirect. Therefore, in this work, the electrostatic potential distribution in nano-scale grains of non-stoichiometric MAS (MgO∙0.95Al2O3,MgO∙1.07Al2O3and MgO∙1.27Al2O3) was measured by off-axis electron holography and compared to the distribution of cations and defects in this material as measured by electron energy-loss spectroscopy. In this manner, we studied the roles of composition, grain size and applied electric field on the formation of a space-charge region.We quantitatively demonstrated that regardless of grain size, the vicinity of MgO∙0.95Al2O3grain boundaries presented an excess of Mg+2 cations, whereas the vicinity of MgO∙1.07Al2O3grain boundaries included an excess of Al+3 cations.The degree of structural disorder (i.e., the inversion parameter, i) indicated that as-synthesized MAS were significantly disordered (i between 0.37 and 0.41), with valuesdecreasing toward equilibrium ordering values following annealing (i between 0.27 and 0.31). The application of an external 150 Vcm-1electric field during annealing further enhanced lattice ordering (i between 0.16 and 0.19).Such variations in the distribution of cations and defects should determine the SCP. However, using these measurements to calculate the SCP was not possible due to the wide range of values reported for formation energies of defects (0.82-8.78 eV). Consequently, we correlated local ionic ordering with electrostatic potential in non-stoichiometric MAS. The magnitudes of the SCP in both MgO∙0.95Al2O3 and MgO∙1.07Al2O3decreased following annealing from -3.4±0.3V and +2.0±0.2 V to -2.0±0.2 V and +1.6±0.1 V, respectively.Such results underscore the importance of comprehensive nanometer scale characterization of the chemistry and electrostatic potential and providing a comprehensive understanding of defects in complex oxides.
|Start at||Subject View All||Num.||Add|
Composites for biomedical applications,part 1 : Dr IRYNA BILAN
Authors : I.V. Uvarova, V.D. Klipov, V.P. Sergeev, E.V. Shcherbitska
Affiliations : Frantsevich Institute for Problems of Materials Sciences of NASU
Resume : Carbon fiber activated nanostructured materials(CFANM) prepared by one stage pyrolysis of rayon have been investigated as materials of sorption action for using in medicine and environmental protection. As established they belong to group of granular–fibrillar composite anisotropic nanostructured materials which consist of different types of nanofibers and granular nanoparticles as carbon nanopackets withSiO2activation addition.CFANMhave widened systems of micro- (0,6<х<1,5 nm), meso- (1,5<х<200 nm)and macro-(х<300 nm)pores as well as specific surface area of 2800 m2/g.The total porous volume and microporosity increase with a degree of rayon transformation. For increasing the sorption characteristics of investigated materials their modification by oxidation of nitric acid solution of different concentration have been carried out. Proposed technology at the same activation extent and total porosity allows obtaining a different porous distribution and as a result supplies with regulative adsorption of toxic substances of different molecular mass by change of parameters for technological process.As established an application of proposed carbon fibrous nanostructured materials is one of most effective methods of detoxification therapy under poisoning by xenobiotics as well as poisons of chemical and bacterial nature. The processes of immobilization of biological active compounds such asa ferrocene, quercetyne, lipase, antibiotics, alkaline proteaseon the surfaces of prepared sorbents as well as sorption of organic components such as phenol,heavy toxics metals, low-molecular substance, albumin were investigated.
Authors : E. Iordanova-1, G. Yankov-1, N. E. Stankova-2 , Ru.G. Nikov-2, R.G. Nikov-2, P.A. Atanaso-v2, K.N. Kolev-3, Dr. M. Tatchev-3 , M. Grozeva-1
Affiliations : 1-Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia, Bulgaria; 2-Institute of Electronics, Bulgarian Academy of Sciences, Sofia,Bulgaria; 3-Rostislaw Kaischew Institute of Physical Chemistry, Bulgarian Academy of Sciences, Sofia. Bulgaria
Resume : This research concerns investigation on medical grade polydimethyl siloxane (PDMS) elastomer irradiated by fs-laser. The motivation is based on the wide use of the PDMS material in medicine and medical devices. The application in the medical field is due to some of the main properties of the PDMS. Thus its high biocomatibility and biostability, mechanical flexibility and chemical stability, optical transparency from UV to near IR spectral region. The experimental setup consists of fs-laser system, optical parametric amplifier, optical elements and XYZ translating stage. The regenerative Ti:Sapphire amplified laser system has a pulse duration of 35 fs and 1 kHz repetition rate. The working parameters as laser fluence and number of pulses are varied. Specifically, the laser fluence applied is between 0.16 and 0.5 J.cm-2 and the number of consecutive pulses is from 102 to 104. Additionally, the wavelengths used in the experiments are 266, 355 and 532 nm. Tranches on the PDMS-elastomer MED 4860 surface are produced by the fs-laser processing and the material inside them is modified. Optical properties and morphology of the trances are investigated in terms of the laser beam parameters. Despite the low optical absorption of the native PDMS for UV, VIS and NIR wavelengths, successful laser treatment is accomplished due to the chemical transformations occurring below the polymer surface. The optical absorption and thus saturation caused by the incubation process is observed with the increase of the number of pulses. Such process increases significantly the efficiency of the laser ablation. The ablation depth measured is in the range of 4 ÷ 10 ?m for UV light and in the range of 10 ÷ 40 ?m for VIS laser treatment, respectively.
Authors : N. Kaplunenko, N. Ulyanchich, I. Uvarova
Affiliations : Frantsevich Institute for Problems of Materials Sciences of NASU
Resume : In modern medicine hydroxyapatite (HAP) is the most widespread material-substitute of damaged bone tissue due to its biochemical composition similar to hard tissue of all the vertebral being and high biocompatibility with the living organism. But hydroxyapatite based materials have poor physic-mechanical properties under heightened loadings. Basalt scale has been chosen for strengthening HAP and improvement of its physic-mechanical characteristics as well as because of its biological inertness. Stochiometric HAP of different fractional composition strengthening by amorphous – crystal basalt scale (0 %, 5 %, and 10 %) has been investigated in this work. Pressed samples were sintered under 700 оC, 800 оC, 900 оC, 950 оC, 1070 оC, 1250 оC and their phase composition and physic-mechanical (shrinkage) properties were investigated. Samples of HAP with 5 % of basalt scale which were sintered at 1250 оC demonstrated the best result. They exceeded ruling analogs by their mechanic parameters as well as they were compactness similar to bone tissue. In this case bone tissue is able to grow through implant material. X-Ray analysis showed β-ТКФ phase formation. This phase is the most compatible with the living organism. It was established that basalt scale sintered under 1250 оC was very stable in the media which imitated the media of living organism and it is biocompatible too. Thus, HAP strengthening by amorphous – crystal basalt scale is very perspective implant material.
Authors : Olena Sych-1, Artem Iatsenko-2, Hanna Tovstonoh-1, Tamara Tomila-1, Yan Yevych-1
Affiliations : 1-Frantsevich Institute for Problems of Materials Science of NAS of Ukraine, Kyiv, Ukraine 2-National Technical University of Ukraine "Kyiv Politechnical Institute", Kyiv, Ukraine
Resume : Hydroxyapatite (HA) bioceramics doped with various ions are gaining more interest in the field of tissue engineering applications. Of the many trace elements or ions, fluorine is most commonly employed as an additive in HA due to similarity of HA and fluorapatite structures. Fluorine actively participates in bone formation, the processes of formation of dentin and enamel. In the present work highly porous glass-ceramics based on biogenic HA (BHA) and SiO2-CaO-Na2O glass with fluorine addition (0.3 wt. %) have been prepared by foam replica technique at sintering temperature 900 °?. Under sintering BHA decomposes with the formation of glass-ceramics due to the aggressive action of the glass phase, which results in forming phases such as: renanit NaCaPO4 (JCPDS, Card No. 76-1456), calcium silicate phosphate Ca5(PO4)2SiO4 (JCPDS, Card No. 21-0157), calcium pyroposphate ??2?2?7 (JCPDS, Card No. 33-0297) and impurities of HA Ca5(PO4)3(OH) (JCPDS, Card No. 09-432). Fluorine addition also leads to the formation of fluorapatite Ca5(PO4)3F (JCPDS, Card No. 02-0845), which was confirmed by IR spectroscopy results. It was established that fluorine introduction retains permeable porous structure of the material (porosity ~ 80 %) without compromising the structural and mechanical properties of the samples, as well as insignificantly reduces the solubility in vitro, which makes them promising for the treatment of bone diseases in orthopedics and traumatology.
Authors : O. Otychenko, T. Babutina, O. Ivashchenko, O. Budylina, L. Protsenko, E. Shmeliova, I. Uvarova
Affiliations : Frantsevich Institute for Problems in Materials Science, 3, Krzhizhanovsky str., Kyiv, Ukraine, 03680 National Technical University of Ukraine «Kyiv Polytechnic Institute», 37, Peremohy av., Kyiv, Ukraine, 03056 NanoBioMedical Centre, Adam Mickiewicz University in Poznan, 85, Umultowska str., PL 61614, Poznan, Poland
Resume : Foregoing bioactive material for medical application has been obtained by impregnation of nanostructured biogenic hydroxyapatite (BHA) microgranules (?160 µm), prepared according with T? ? 33.1-22965991.002-2001 by 1 and 2 ml of colloidal solution of magnetite with following mechanical mixing impregnation powder. This composite materials were thermally treated in a nitrogen-containing medium at 500 º?, that less than the Curie point for magnetite (572 ºC), for 2 hours. ?hemical composition of prepared compounds (before and after thermolysis) have been controlled by photocolorimetric method. According to photocolorimetric analysis, material doped with 1 ml colloidal solution of magnetite had 0.59 (%) mass. of total iron before heat treatment, and 0.52 (%) mass. ? after it. For the sample doped with 2 ml colloidal solution of magnetite the amount of total Fe was 0.68 (%) mass. and 0.69 (%) mass. before and after thermolysis, respectively. Thus, this type of heat treatment keeps the chemical composition of the investigated materials.
Composites for biomedical applications, part 2 : Prof. IRYNA UVAROVA
Authors : Rudenchyk T.V.; Rozhnova R.A.; Galatenko N.A.
Affiliations : Institute of Macromolecular Chemistry of NAS of Ukraine
Resume : Previously we have synthesized compositions based on oligooxypropylene fumarate, thriethylene glycol dimethacrylate and N-vinylpyrrolidone, which contain immunomodulator levamisole proposed for creation of bone implants. One of the necessary steps in creating biologically active composite materials intended for use as implants is the study of biodegradation under conditions close to the medium of the human body. The ability to biodegradation studied the change in their physical-mechanical properties and structure under the influence model biological medium 199 (BM 199), which imitates the blood plasma. Samples of composites were incubated in BM 199 at a temperature of 37 ± 1°C for the period of 1 and 3 months. Based on the results of physical-mechanical tests, after incubation in BM 199 of investigated composite materials, occurs decrease modulus of elasticity in compression, which indicates the course of biodegradation of polymer base these materials by ester and ether bonds (according to IR-spectroscopic) under the influence of BM 199. Therefore, the studied composite materials based on oligooxypropylene fumarate, thriethylene glycol dimethacrylate and N-vinylpyrrolidone, which contain immunomodulator levamisole have the ability to biodegradation and can be used as a basis for creating drug delivery systems.
Authors : L.V. Karabanova(1), Yu.P. Gomza(1), S.D. Nesin(1), O.M.Bondaruk(1), L.V. Nosach(2) , E.P. Voronin(2)
Affiliations : (1) Institute of Macromolecular Chemistry of NAS of Ukraine, Kharkov Road 48, Kiev 02660, Ukraine, e-mail:email@example.com (2) Chuiko Institute of Surface Chemistry of NAS of Ukraine, 17 General Naumov Str., Kyiv 03164
Resume : The nanocomposites based on multicomponent polymer matrix consisting of polyurethane (PU), poly (2-hydroxyethyl methacrylate) (PHEMA), and nanofillers based on silica with mechanically activated surface and surface modified by aminoacid glycine are synthesized. The structure of the nanocomposites and thermodynamic parameters of polymer components with nanofiller interaction were studied. The structure of the created nanocomposites was investigated by small-angle X-ray scattering and was shown that modification of densil surface by aminoacid glycine leads to an increase of average size of the particles and to the formation of a rough surface of filler. Introduction of modified nanofiller into polymer matrix influenced the structure of the matrix: there is a complete disappearance of the structural features of semi-IPN in the nanocomposites. With the introduction of the modified nanofiller into polymer matrix the mass-fractal of spatial distribution of the particles is preserved. However, the surface roughness of the particles increases. The thermodynamic parameters of interaction between polymer matrix and nanofiller were investigated. It was shown that the free energy of mixing of polyurethane, PHEMA and semi-IPNs with filler is negative for systems with low content of PHEMA, and thus the energy is released during process of the nanocomposites formation, and dence, durable polymer layers on the surface of nanofiller are formed. With increasing the PHEMA content the free energy of mixing moves to the positive value, which is the result of competition of two processes: formation of dense surface layers on the surface of the filler, and the formation of interfacial layers with excess free volume. Acknowledgement The work was supported by the project N 188.8.131.52 of the STSTP “Nanoteсhnology and Nanomaterials” of Ukraine
Authors : Yu. V. Savelyev, A. N. Gonchar, T.V. Travinskaya
Affiliations : Institute of Macromolecular Chemistry of NASU
Resume : Biologically active metal containing polyurethane materials based on colloid solutions of silver and copper naoparticles in polyether have been prepared. Obtaining of colloidal metals (Ag, Cu) solutions in polyether was carried out by Electron beam physical vapor deposition (EB- PVD). Metal nanoparticles concentration in obtained material compositions was varied from 200 to 600 ppm. Biological study of Cu and Ag nanometals containing polyurethane has shown that they exhibit bactericidal properties in relation to both gram-positive and gram-negative bacteria, and Candida fungi. Synthesized polyurethanes possess bacteriostatical effect on fungi - micromycets. Obtained biologically active metal containing polyurethane materials can be processed into goods for medical purposes (catheters, drains, films, grids and so on) by standard methods of polyurethane processing, as the presence of metal nanoparticles in their structure does not affect the physical properties of the polymer.
|Start at||Subject View All||Num.||Add|
Composites for optics and electronics:part 1 : Dr. IRYNA BILAN
Authors : Sébastien Maron, Nadège Ollier, Thierry Gacoin, Géraldine Dantelle
Affiliations : Physique de la Matière Condensée - École polytechnique/CNRS ; Laboratoire des Solides Irradiés - Commissariat à l'Énergie Atomique/École polytechnique/CNRS ; Physique de la Matière Condensée - École polytechnique/CNRS ; Institut Néel - CNRS
Resume : Determining the doping level is essential to optimize the properties of materials, e.g. luminescence. We present an original high-accuracy method based on the 31P solid-state NMR relaxation to determine low concentrations (< 1 %) of paramagnetic lanthanide ions. Our method was first applied to a model compound, LaPO4, within the doping incorporation is known. NMR experiments under static and MAS conditions reveal that the 31P relaxation time T1 is strongly affected by the presence of paramagnetic ions in the vicinity of the phosphorous nuclei. A linear variation of 1/T1 as a function of neodymium (Nd3+) or gadolinium (Gd3+) concentration is shown in the 0-10 at.% range for a homogeneous distribution of the doping ions in the matrix. Our method is compared to a classic one: the evolution of cell parameter. The electronic relaxation times of Gd3+ and Nd3+ have been evaluated by ESR measurements under saturation conditions. This allows us to provide a semi-quantitative interpretation of the nuclear 31P relaxation measurements. We generalize our method to other crystalline (xenotime, apatite) and amorphous materials (phosphorous glass) to understand which parameter (structure, length) could influence the relaxation time.
Authors : Karolina Pietak-1, Dorota Brzuska-Kamoda -1, Daniel Jastrzebski-1, Grzegorz Matyszczak-1, Michal Wrzecionek -1, Piotr Pietrzak- 1, Maciej Bialoglowski -1, Slawomir Podsiadlo-1, Cezariusz Jastrzebski -2
Affiliations : 1- Faculty of Chemistry, Warsaw University of Technology, Warsaw, Poland; 2- Faculty of Physics, Warsaw University of Technology, Warsaw, Poland
Resume : Energy management indicates that in the future the main source of electricity will be renewable energy sources. Constant interest of new cheap, efficient and ecological photovoltaics devices stimulates study of new semiconductor materials and structures. CIGS (CuGaxIn1-xSe2) is supposed to be good compound for solar cells. However the high prices of Ga and In cause that to seek to the different materials with similar properties, whose energy gap will have a value 1,2 ? 1,5 eV. Cu2ZnSnS4 (kesterite) is a semiconductor that corresponds with all these requirements. The formation of it was investigated by thermal analysis during studies on the reactivity of CuS, ZnS and SnS2. The products were studied using X-ray measurements, electron microprobe and Raman spectroscopy.
Authors : Sangyoon Ji, Byung Gwan Hyun, Kukjoo Kim and Jang-Ung Park*
Affiliations : School of Materials Science and Engineering, Wearable Electronics Research Group, Smart Sensor Research Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, 44919, Republic of Korea
Resume : Substantial progress in flexible or stretchable electronics over the past decade has extensively impacted on various technologies such as wearable devices, displays, or automotive electronics for smart cars. An important challenge here is reliability of these deformable devices against thermal stress. Different coefficients of thermal expansion (CTE) between plastic substrates and the device components which include multiple inorganic layers of metals or ceramics induce thermal stress to the devices during fabrication processes or long-term operations with repetitions of thermal cyclic loading-unloading, lead to device failure and degrade their reliability. Here we report an unconventional approach to form photo-patternable, transparent cellulose nanofiber (CNF) hybrid films as flexible and stretchable substrates toward reliable devices, using simultaneous electrospinning and spraying. The electrospun polymeric backbones and sprayed cellulose nanofiber fillers enable the resulting hybrid structure to be patternable photolithographically as a negative photoresist, and stable thermally and mechanically, with presenting outstanding optical transparency (~ 89 %) and low CTE (< 10 ppm/K). We also formed stretchable, origami substrates using the CNF hybrid, which are composed of rigid support fixtures and elastomeric joints, exploiting the photo-patternability. Demonstrations of transparent organic light-emitting diodes and touch-screen panels on the hybrid film suggest a promise for next generation electronics.
Authors : Byeong Wan An1, Eun-Ji Gwak2, Kukjoo Kim1, Young-Geun Park1, Young-Cheon Kim2, Jiuk Jang1, Ju-Young Kim2, Jang-Ung Park1
Affiliations : 1: School of Materials Science and Engineering, Wearable Electronics Research Group, Center for Smart Sensor Systems, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, 44919, Republic of Korea 2: School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, 44919, Republic of Korea
Resume : Mechanical robustness, electrical and chemical reliabilities of devices against large deformations such as bending and stretching have become the key metrics for rapidly emerging wearable electronics. Metallic glasses (MGs) have high elastic limit, electrical conductivity, and corrosion resistance, which can be promising for applications in wearable electronics. However, their applications in wearable electronics or transparent electrodes have not been extensively explored so far. Here, we demonstrate stretchable and transparent electrodes using CuZr MGs in the form of nanotrough networks. MG nanotroughs are prepared by electrospinning and co-sputtering process, and they can be transferred to various desired substrates, including stretchable elastomeric substrates. The resulting MG nanotrough network is first utilized as a stretchable transparent electrode, presenting outstanding optoelectronic (sheet resistance of 3.8 Ω/sq at transmittance of 90%) and mechanical robustness (resistance change less than 30% up to a tensile strain of 70%) as well as excellent chemical stability against hot and humid environments (negligible degradation in performance for 240 h in 85% relative humidity and 85 °C). A stretchable and transparent heater based on the MG nanotrough network is also demonstrated with a wide operating temperature range (up to 180 °C) and excellent stretchability (up to 70% in the strain). The excellent mechanical robustness of these stretchable transparent electrode and heater is ascribed to the structural configuration (i.e., a nanotrough network) and inherent high elastic limit of MGs, as supported by experimental results and numerical analysis. We demonstrate their real-time operations on human skin as a wearable, transparent thermotherapy patch controlled wirelessly using a smartphone as well as a transparent defroster for an automobile side view mirrors, suggesting a promising strategy toward next-generation wearable electronics or automobile applications.
Authors : A. BENZAOUAK,N. TOUACH, N. LABJAR, C. JAMA, M. EL MAHI and E. M. LOTFI *
Affiliations : LM2PI, Chemical Sciences Research Team, ENSET, Mohammed V University in Rabat. Morocco
Resume : A lithium tantalate is recognized by their exceptional proprieties piezoelectric, pyroelectric, and ferroelectric and no linear optic. These properties are extremely sensitive to inserting metals elements. In this work, we are interesting to insertion the hexavalents elements as W6+ in LiTaO3 phase. The polycrystalline solid solutions Li1-xTa1-xWxO3 (0 ≤ x ≤ 0.25) has been synthesized at 800°C and investigated by using high-temperature XRD, neutrons powder diffraction RT, PSD, MET, MEB and UV spectroscopy. The ferroelectrics transitions had been observed by XR diffraction analysis for all studied phases. The refinement of neutrons diffraction reveals the types of non stoichiometric formulas. It has been demonstrated that the tungsten W6+ is certainty localized on the [Ta] site and probably present in tetrahedral sites for x=0.10 with occupancy rate not exceeding 1% in the accuracy limit of the used technic. In other hand, using laser diffraction spectroscopy (PSD), the particle sizes increase with varying W6+ concentration (1 to 50 µm) accompanied with reduction of original population of particles class LiTaO3. The UV spectroscopy technic gives the energy bandgap, the values are near 4.81 and 3.85 eV in LiTaO3 and Li0.90Ta0.90W0.10O3 respectively for example, indicating the tungsten can improve the light absorption due, probably, to photochromic tungsten effect.
Authors : T. A. Prikhna-1, M. Eisterer-2, W. Goldacker-3, G. E. Grechnev-4, V. Sokolovsky-5, A. P. Shapovalov-1, A.V. Kozyrev-1, V. E. Moshchil-1, V. B. Sverdun-1, H. W. Weber-2, V. G. Boutko-6 A. A. Gusev-6, W. Gawalek-7, V. V. Kovylaev-8, M. V. Karpets-8, T. V. Basyuk-1
Affiliations : 1-Institute for Superhard Materials of the NASU,Ukraine; 2-Atominstitut, TU Wien, Austria; 3-Karlsruhe Institute of Technology (KIT), Germany ; 4 -B.Verkin Institute for Low Temperature Physics of NASU, Kharkov, Ukraine; 5- Ben-Gurion University of the Negev, Beer-Sheva , Israel; 6 -Donetsk Institute for Physics and Engineering named after O.O. Galkin of NASU, Donetsk, Ukraine; 7- Magnetworld AG, Jena, Germany; 8-Institute for Problems in Material Science of NASU,Kiev, Ukraine
Resume : Despite the presence of a rather high amount of impurity oxygen in their structure the materials demonstrate excellent superconducting properties, such as jc (~106 A/cm2 in 0-1 T at 20 K), upper critical fields, Bc2 (42.1 T at 0 K, 15 T at 22 K), and trapped magnetic fields (1.9 T at 20 K in a 10 mm thick sample of 30 mm in diameter). The presence of Ti (just in contact with the sample or by addition to the precursors) during synthesis can affect the distribution of the impurity oxygen and hydrogen in MgB2 thus influencing the superconducting characteristics and giving the possibility to increase the critical current density, jc (Birr, Bc2), reduce porosity and avoid cracking. Synthesis under 2 GPa – 30 MPa pressure allows the preparation of highly dense MgB2 with 50- 80 % connectivity and a shielding fraction of 75-100%. The materials are promising for the generation of high magnetic fields and fault current limiters. AC losses per cycle of around 0.75-1 J/cm3, were measured by using the transformer method while the power loss was about 200 W. The distribution of the impurity oxygen can be regulated by synthesis temperature and Ti addition. It affects jc of high pressure MgB2 to a high extend due to the formation of oxygen-enriched Mg-B-O nanolayers or nanoinclusions and higher magnesium borides MgBx (x>4). Oxygen is partly dissolved in the MgB2 matrix, as an Auger study revealed. The calculation of the density of states (DOS) of Mg(B1-xOx)2 showed that all compounds are conductors with a non-zero DOS at the Fermi level. For x0.25 the DOS is even somewhat higher than in pure MgB2 and the binding energy is similar. A high amount of H leads to porosity in MgB2 and MgH2 formation, which correlates with a jc decrease. The manufacturing of large (30-150 mm) crack-free samples under pressure is practically impossible without Ti. Its high affinity to H (higher than that of Mg) absorbs impurity H by forming TiH2.
Composites for optics and electronics:part 2 : Dr. IRYNA BILAN
Authors : K.-H. Heinig-1, 2, E. Schumann -1, J. Kelling -1, M. Vinnichenko-2
Affiliations : 1- Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany; 2- Fraunhofer Institut für keramische Technologien und Systeme, Dresden, Germany
Resume : Composite materials substitute more and more single component materials. Nanocomposites can have superior properties which originate from their huge interface area and small structure sizes. For instance, due to quantum confinement, the electronic bandgap of sponge-like silicon embedded in SiO2 is larger than that of bulk Si, and it can be even tuned by the fabrication process. Thus, due to the bandgap adjusted to the solar spectrum, such nanosilicon is a promising material for photovoltaics [APL103(2013)131911, APL103(2013)133106, APL103(2013)203103), NanoLetters16(2016)1942]. Furthermore, due to its huge capillary forces, a sponge-like nanoceramics can be used to immobilize efficiently high-temperature melts. This makes a nanoporous composite of chemically stable ceramics an interesting material for energy conversion and storage applications. Here, we present experimental studies and large-scale atomic computer simulations on the spinodal decomposition and the coarsening process of the nanostructure. It will be shown that the spinodal decomposition can occur by solid state processes as well as in the liquid state if the components are immiscible. Liquid-state decomposition is performed at a millisecond time scale using a diode laser scan. Although the liquid-state decomposition is about a million times faster than the solid state decomposition, the mean nanostructure length is about 10x higher.
Authors : P.S. Smertenko-1, D.A. Grynko-1, A.N. Fedoryak-1, O.P. Dimitriev-1, N.A. Ogurtsov-2 and A.A. Pud-2
Affiliations : 1- V.Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kyiv , Ukraine 2-Institute of Bioorganic Chemistry and Petrochemistry, NAS of Ukraine, Kyiv, Ukraine
Resume : CdS nanowires-polymer composite was prepared on a single carbon fibre. A carbon fibre with the resistivity of ~3.8*10 3 Ohm*cm, the diameter of ~5?10 ?m and the length of ~15?30 mm was served as the electrode. As the top electrode the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) has been drop-cast from the 1.3 wt.% water dispersion. Zinc phthalocyanine (ZnPc) or Poly(3-hexylthiophene) (P3HT) served as organic donor counterparts. The current-voltage characteristics (CVC) of following composites were investigated: (i) Solid-State Dye-Sensitized Solar Cell (SSDSSC); (ii) Electrochemical Dye-Sensitized Solar Cell (DSSC). It was found that behaviour of charge carriers in the SSDSSC structure obeys mainly the power-law dependence with ??=?2 that corresponds to the first-order (monomolecular) recombination with p?>>?n, that means that concentration of the injected minority charge carriers is not enough for effective transport in the structure. In the case of the DSSC structure, the charge carriers behaviour follows the cubic dependence with ??=?3. In both structures the interface of CdS nanowires with ZnPc-4R plays the main role in formation of photo-generated charge carriers. On the base of analysis of the CVC curves the suggestions for optimization of the composites for PV application can be formulated: (i) to decrease substantially the bulk resistance in SSDSSC and DSSC; (ii) to improve injection of both types of charge carriers from the contacts in case of SSDSSC; (iii) to use a tighter CdS layer around the CF electrode to escape shortcutting problems in SSPSSC and ISP composites and (iv) to replace the CdS layer for the p-type semiconductor. The possible application of investigated composites for solar cell is discussed. Financial support of CRDF project No. UKE2-7035-KV-11.
Authors : A. Naumov (1), A. Apsitis (2), J. Blahins (2), A. Ubelis (2), S. Vitusevich (3), A. Belyaev (1)
Affiliations : (1) Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, Kiev 03028, Ukraine; (2) Institute of Atomic Physics and Spectroscopy, University of Latvia, Riga LV-1586, Latvia; (3) Peter Grünberg Institute, Forschungszentrum Jülich GmbH, Jülich 52425, Germany
Resume : Complex 1D/2D nanowire structures based on AIII-BV compounds due to their unique physical-chemical and electrical properties are very attractive for micro-, nano- and optoelectronic applications including bio-electronic sensing [A. Naumov et al. (2016) J Appl Phys, in press]. We studied electric current-voltage (I-V) characteristics of gallium-nitride (GaN/AlGaN) transistor-type (HEMT) planar heterostructures (HS) with nanowires (NW) grown by MOCVD method on dielectric substrates (sapphire c-Al2O3) and fabricated by electron-beam lithography and laser ion-beam etching in a form of 600 nm long strips of different widths 185-1110 nm. Ohmic contacts were made by sputtering Ti / Al / Ni / Au nanolayers and annealing at 900 C. The conducting channel in quantum wells (QW) with a two-dimensional electron gas (2DEG) in the HEMT structure is near the gate surface and is extremely sensitive to the environment. NW elements add more surface area to increase the sensitivity required for the detection of biomarkers in bio-sensing at the atomic and molecular levels. Systematic optical and electrical measurements showed an excellent sensitivity of such NWs to micro- and nanodroplets of buffer solution with different index pH = 5-9. For the broad NWs (1110 nm) the ratio of output current to the sensor current at the gate is 1.3-1.5, for the narrow NWs (280 nm) this ratio is 1.36-1.32 (at voltages of ~ 2 V). For the finest NWs (185 nm) the current-voltage changes during incubation of droplets are hardly observed. The results obtained demonstrate the potential use of complex nanowire HEMT structures as bioelectronic sensors. Research is in progress. Support of the DAAD, BMBF and FP7 project FOTONIKA-LV at Latvian University is gratefully acknowledged.
Authors : L. Kernazhitsky -1, V. Shymanovska-1, T. Gavrilko -1, V. Naumov -2, P. Smertenko -2, J. Kleperis-3, V. Skryshevsky -4
Affiliations : 1- Institute of Physics, National Academy of Sciences of Ukraine, Kiev 03028, Ukraine; 2- Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, Kiev 03028, Ukraine; 3- Institute of Solid State Physics, University of Latvia, Riga LV-1068, Latvia; 4- Institute of High Technology, Taras Shevchenko National University of Kyiv, 03022 Kiev, Ukraine
Resume : Titanium-manganese mixed oxides, TiO2/MnOx (TMO) are one of the most remarkable functional materials in a family of metal-oxide semiconductors, which have enhanced photoactivity in response to light and capabilities of various energy and environmental applications including photovoltaics, photocatalysis and photosensors. We studied nanostructured TMO composites with different Mn content. High-purity TMO samples were synthesized by chemical precipitation of manganese hydroxide on the surface of TiO2 particles, followed by thermal treatment at different temperatures. The samples were characterized by XRD, FTIR, Raman, UV-VIS optical absorption and PL emission spectroscopy. According to XRD spectra, nanocrystalline TMO calcined at 300оС have Mn2O3 phase, while TMOs annealed at 900оС have the MnTiO3 phase. FT-Raman spectra revealed the existence of different transient MnOx crystal phases resulting transformations upon thermal treatment. FTIR spectra observed in the region of internal and lattice vibrations (400 800 cm-1) of TiO2, Mn2O3 and MnTiO3 suggest the existence of different oxidation levels and structural defects. UV-VIS absorption spectra show a significant shift of the absorption edge toward longer wavelengths, implying the reduction in the band gap as compared with pure TiO2. For TMO with Mn of 15at.% the Ea value is of 2.4 eV. PL spectra of TMO in its main features are similar to those of TiO2, but differ in their intensities. At high contents of Mn (above 8%), due to the increasing number of non-radiative recombination centers, the PL intensity is lower. These results demonstrate the potential use of TMO. Research is in progress. Support of the FP7 project FOTONIKA-LV at Latvian University is gratefully acknowledged.
Authors : V.F. Zinchenko, E.V. Chygrynov
Affiliations : A.V. Bogatsky Physico-Chemical Institute of NASU
Resume : Film-forming materials (FFМ) are used as initial substances for obtaining coatings by PVD (Physical Vapor Deposition) method more often. In a CVD (Chemical Vapor Deposition) method the coating is formed in a course of gaseous reactions between volatile components. Earlier we developed composite FFМ on the basis of system Ge-ZnS, evaporating congruently at rather low temperatures. Evaporation in vacuum and condensation on a substrate of such kind of material combines in itself the features of both PVD, and CVD processes. The calculated value of conditional temperature (Tc=TP≈1.33Pa) for composite named CVD - composite (590°С) is much lower, than for ZnS (820°C) and for Ge (1410°C). Thus, according to XRDA, the nano-composite type coating occurs though the initial material being microcrystalline. It makes possible to improve essentially optical and operational (especially, mechanical durability) parameters of coatings. In addition to their application as FFМ of new type, they are used, for example, in a finishing stage of a way of deep clearing of zinc sulfide from oxide admixture. Surplus of the sulfidizing agent, Sb2S3 is eliminated by processing with an additive of highly dispersed Ge. Other CVD-composites as FFМ on the basis of binary compounds are investigated also, namely: Ge-ZnSe, Ge-Sb2Se3, Ge-In2Se3, Ge-EuS, Ge-EuSe, Ge-ZnO, Ge-GeO2, etc. Considerable part of this series has shown high level of optical and operational parameters of coatings.
Advanced technologies of composite production:part 1 : Dr. IRYNA BILAN
Authors : A.Ph. Ilyushenko, V.V.Savich
Affiliations : SSI «Powder Metallurgy Institute»
Resume : The ASTM F2792.15493231 standard is the definition of additive technologies: Additive Manufacturing - the process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing technologies - the process of combining materials to create an object on the basis of data 3D- model, as a rule, layer by layer, in contrast to the «subtracting» production technology. In this definition, three key points: the compound material; Computer 3D-model; Unlike metal cutting machining technologies, which are defined as «subtractive» technology. Lamination with the definition used «as a rule», that is, may not be required. Thus, the compounds of technology components in disperse the finished product in the same process - by definition, are additive. Technology of powder metallurgy, which are used in industry for more than a hundred years, could reasonably be attributed to the industrial additive technologies. The grounds for such a statement as follows: - Raw material powder metallurgy - in disperse form; - Feedback on particulate feedstock pressure and temperature - the finished product 3-D finite size and shape; - Improving the powder properties of the product is achieved by increasing its density.
Authors : Yuryi Dorofeyev, Vladimir Dorofeyev, Alexander Babets, Nickolay Petrov
Affiliations : Platov South-Russian State Polytechnic University
Resume : Poor compressibility of high-speed steels’ powders necessitates the use of additional operations at the technological conversion (Stamp-process: filling capsules with powder, evacuating and sealing, heating, isostatic compaction of capsules, forging or drop stamping). The appearance on the market of compressible atomized high speed steel M2 powder with low oxygen content at the expense of vacuum reduction has provided an opportunity to reduce the number of technological transitions. Various technological schemes of production of high speed steel based on M2 powder by hot forging of porous preforms were studied in this paper. In accordance with the first scheme cold-pressed preforms were hot forged. At the implementation of another scheme prior to forging preforms were sintered in a disassociated ammonia environment. Following hot forging heat treatment was carried out (quenching + tempering). These samples were mechanically tested in parallel with the witness samples made from cast steel. The optimal technological modes of hot forging, providing production of high density high-speed steel M2, the properties of which are level with the samples-witnesses, have been determined. The possibility was demonstrated to oxidize interparticle surfaces during sintering due to the presence of chromium in the composition of the initial powder. It is recommended to perform the sintering in a protective atmosphere with a low dew-point temperature or to exclude this operation from the manufacturing.
Advanced technologies of composite production:part 2 : Dr IRYNA BILAN
Authors : Krasovskyy V.P., Vishnyakov L.R., Krasovskaya N.A., Kochanyy V.A.,Sydorenko T.V.
Affiliations : I. Frantsevich Institute of Problems of Materials Science of NASU
Resume : Realization of effect of Removal of an electric current allows to regulate process of carry of thermal and electric energy from a place of defeat of carbon-plastic by a lightning. This effect depends on a construction and properties of soldered knots of net. In many electro technical and electronic systems apply metallization and the soldering. Wetting of wire surface by solder at creation of a wire net construction has great value. The sessile drop method with ?capillary purification? method was applied. The wetting of compact materials on the base of pure copper and bronzes (tin, beryllium, aluminum) by the low temperature solders on the basis of tin was studied. Temperature dependences of a contact angle by free lead alloys have shown decrease of size of angles with growth of temperature. Beryllium bronze is wetted by alloys practically as pure copper. At wetting of bronzes Sn?Ag?Cu solder showed the better activity in comparison with alloys Sn, Sn?Pb, Sn?Bi. Results on wetting by O-2, SAC (Sn?3,2 % Ag?0,7 % Cu), CASTIN (Sn?2,5 % Ag?0,7 % Cu?0,5 % Sb) and Sn?Bi alloys of copper and bronzes substrates showed, that copper and beryllium bronze by alloys are wetted better. Sn?Ag?Cu solders, and also Sn/Bi alloys for metallization and soldering of high porous copper net construction were used.
Authors : O. Povstyanoy
Affiliations : Lutsk National Technical University
Resume : The current state of development of powder metallurgy process characterized by continuous enrichment of getting new ideas penetrating porous materials (PPM). However, the solution to these problems of powder metallurgy limited, on the one side, technological capabilities of known techniques and methods for filtering materials [3, 4]and on the other, dependencies number of properties on the parameters of production. Moreover, in practice when creating penetrating porous materials with specified complex performance there are difficulties related to limited features traditional manufacturing techniques. So, to create practical PPM desired porous structure that will meet the optimal combination of performance, it is necessary to establish interconnection between technological regimes and obtain optimum pores distribution of radius by PPM. Method radial isostatic pressing is that unlike more common axial pressing in rigid matrices, the effort applied to the powder in the radial direction. One of the advantages of this method considered the uniformity of density distribution by volume pressing. Indeed, the cost of countering external friction when radial compressions, from this point of view, were an order of magnitude smaller. This fact and was the root cause when choosing a method of obtaining long hollow cylindrical products. Therefore, on the basis of the above, as well as special attention, this takes the matter due to the choice of compression technology. The purpose of this work is to carry out a special study aimed to address the issue of distribution of density in the radius the radially isostatic pressing. To achieve this goal were as the following tasks: • The description of the geometric model of the process of pressing PPM and calculate exertion and speed of deformation at the same; • To determine the field density hollow PPM; To achieve this goal applied continuum plasticity theory porous body in modification proposed . This will be the results, which have a relatively simple analytic view that allow analyzing the factors that contribute to the heterogeneity of distribution of density. The calculations and conducting practical research porosity change when the radius of the cylindrical blanks PPM (hollow cylinder), which is made by radial isostatic pressing. The authors of this research was the analysis and calculation of density distribution radius hollow PPM, which is obtained by radial isostatic pressing. During the theoretical calculations was the result, which has a simple analytical view and allows you to analyze factors that contribute to heterogeneity of distribution of density. This is shown in the course of calculations and experimental verification. Statistical analysis obtained during the measurement characteristics of PPM obtained and displayed graphic depends imaging analysis process structure.
Authors : Vitaliy Yatsenko
Affiliations : Space Research Institute, Kyiv,Ukraine
Resume : This report focuses on the results of the EU project Superlight-weight thermal protection system for space application (LIGHT-TPS). The bottom line is an analysis of influence of the free space environment on the superlight-weight thermal protection system (TPS). This report focuses on new methods that based on the following models: synergetic, physical, and computational. This report concentrates on four approaches. The first concerns the syner- getic approach. The synergetic approach to the solution of problems of self-controlled synthesis of structures and creation of self-organizing technologies is considered in connection with the super-problem of creation of materials with new functional properties. Synergetics methods and mathematical design are considered according to actual problems of material science. The second approach describes how the optimization methods can be used to determine material microstructures with optimized or targeted properties. This technique enables one to find un- expected microstructures with exotic behavior (e.g., negative thermal expansion coefficients). The third approach concerns the dynamic probabilistic risk analysis of TPS l elements with complex characterizations for damages using a physical model of TPS system and a predictable level of ionizing radiation and space weather. Focusing is given mainly on the TPS model, mathematical models for dynamic probabilistic risk assessment and software for the modeling and prediction of the influence of the free space environment. The probabilistic risk assessment method for TPS is presented considering some deterministic and stochastic factors. The last approach concerns results of experimental research of the temperature distribution on the sur- face of the honeycomb sandwich panel size 150 150 20 mm at the di?usion welding in vacuum are considered. An equipment, which provides alignment of temperature fields in a product for the formation of equal strength of welded joints is considered. Many tasks in computational materials science can be posed as optimization problems. This technique enables one to find unexpected microstructures with exotic behavior (e.g., negative thermal expansion coefficients). The last approach is concerned with the generation of realizations of materials with specified but limited microstructural information: an intriguing inverse problem of both fundamental and practical importance. Computational models based upon the theories of molecular dynamics or quantum mechanics would enable the prediction and modification of fundamental materials properties. This problem is solved using deterministic and stochastic optimization techniques. The main optimization approaches in the frame of the EU project ?Superlight-weight thermal protection system for space application? are discussed. Optimization approach to the alloys for obtaining materials with required properties using modeling techniques and experimental data will be also considered. Acknowledgements.This work has received funding from the EU FP7 Project “Super Light-Weight Thermal Protection System For Space Application" (LIGHT-TPS) under Grant Agreement no. 607182
Authors : 1-A. Ovsienko, 1-Ya. Diatlova, 1-V. Rumyantsev, 2-S. Ordanyan
Affiliations : 1-Virial Ltd;2-Saint-Petersburg State technology institute
Resume : Due to specific interatomic interactions based on complex electron exchange of 2s22p boron atom and 2s22p2 carbon atom, as well as due to development of the complex crystalline structure, boron carbide demonstrates a unique combination of attractive properties, offering potential for wide-ranging advanced applications. High hardness (45 GPa), high E modulus (450-470 GPa), high melting point (2450 оС), lesser density (2.52 g/cm3) are driving current interest in В4С. In addition to the conventional В4С applications in abrasives, boron carbide currently is a popular choice for nuclear energy applications such as control rods and radiation protection, as well as for development of wear-resistant structural and impact-tough ceramics for various applications . At the moment the reaction-bonded boron carbide (RBBC) ceramics sees active development. RBBC is a lightweight composite that comprises many phases, such as silicon (Si), silicon carbide (SiC), complex boron carbide-based carbide phase (B4-хSiyC) and boron carbide (B4C). RBBC is typically processed via silicon melt infiltration into a porous preform at 1450-1650 ºС. Despite lower hardness and wear resistance of RBBC, as compared to the hot-pressed boron carbide (HPBC), the former material offers much more attractive price and a number of other advantages provided by the reaction bonding processing technique. Virial LTD. company has implemented a production of boron carbide parts with max. OD up to Ø300 mm by hot pressing (proThese investigations have been allowed to understand the relation between the processing parameters and the properties of the final RBBC composite has been understood. The choice of premix composition and acceptable time-temperature tolerances when implementing the process in a large industrial-scale reactors have been substantiated.
3 Krzhyzhanovsky Str. , Kiev, Ukrainebelanira2014@gmail.com
ul. Noakowskiego 3 00-664 Warsaw Poland+48 022 660 55 86
+48 022 660 55 86
CH-8600 Dübendorf, Switzerlandthomas.firstname.lastname@example.org
3 Krzhyzhanovsky Str. Kiev Ukraine+380444242073