Materials and coatings for extreme environments

Resume : Ceramics with strength, high hardness, chemical inertness, high melting point are a group of materials for demanding applications as automobile industry, aeronautics, high temperature devices as well as biomaterials. However, the brittleness of ceramics limits the work under stress. The ceramic-metal composites are the solution. There are well described mechanisms of improving the fracture toughness. They depends on various microstructural factors as the combination of ceramics and metal, size and distribution of metal particles or new phases and interfaces. In some ceramic-metal system more than one mechanism of improving fracture toughening can operate. Especially, in composites from ZrO2-Ti system the synergy of toughening mechanisms are possible. Zirconia is the transformation-toughened engineering ceramics. In zirconia-titanium composites Ti might have an influence on the transformation of tetragonal ZrO2 into monoclinic. The incorporation of Ti particles can improve the fracture toughening by mechanism of crack deflection or bridging. Moreover, taking into account possible reaction between Ti and ZrO2 various compounds can be formed and also give synergetic effect into the improving the fracture toughening. In the present review paper the mechanisms of improving fracture toughness in ceramic-metal composites will be described and disused in aspect of their domination in composites. The possible synergy of toughening mechanisms will be analyzed. ACKNOWLEDGEMENTS This work was supported by The National Center of Science (NCN), project DEC-2013/11/B/ST8/00309.

Resume : Magnetic nanoparticles are widely investigated in many areas, where among others can be strongly emphasized medicine and environment protection [1]. Magnetite in nano form is known as non-toxic and well biodegradable, therefore studies on its stability in nanostructures form become interesting for our team. Therefore, investigations of nanostructures resistance in destructive environments have been performed. For such instance, we have chosen few model solutions: distilled water, acetic acid, citric acid, saline, and ethanol [2]. Magnetite nanoparticles were kept in those solutions for certain time, and then analysis of nanoparticles and the solutions were performed. Particles with modified core or surface layer were compared. Examination of nanoparticles before and after treatment in chosen solutions included TEM, IR, X-ray, and Mössbauer spectroscopy studies. The solutions content after experiment were measured by AAS. As a continuation of this studies, are planned tests of nanoparticles behavior in environmental solutions, for instance wastewater and river water. [1] S. Khizroev, M. Kryder, D. Litvinov, D. Thomson, Appl. Phys. Lett. 81 (2002) 2256 [2] B. Kalska-Szostko, U. Wykowska, K. Piekut, D. Satuła, Colloids and Surfaces A: Physicochemical and Engineering Aspects 450 (2014) 15-24

Resume : The aim of the presented work is an evaluation of wood polymer composites for application in power products. Samples based on polypropylene, polystyrene, polyoxymethylene, acrylonitrile butadiene styrene, polyester resin and polylactic acid with different contents of cellulose fibers were prepared by injection molding process. The mechanical and dielectric properties of these composites were studied in order to check whether investigated wood polymer composites fulfil requirements for their application in power products. For all tested composites a linear increase of modulus with cellulose content was observed. Addition of cellulose to the tested polymers significantly reduces strain at break. In the case of polypropylene and polyoxymethylene composites, the tensile strength increases with the content of the filler. For other materials, there is an inverse relationship, namely addition of cellulose decreases the tensile strength. The electrical strength decrease was observed with increased cellulose content for majority of investigated composites. Polar groups incorporated by cellulose fibers have led to dielectric constant increase. Furthermore, aging of composites in mineral oil and evaluation of water uptake for wood-plastic samples were performed. Wood polymer composites have changed significantly after aging. The water diffusion coefficients were determined and the significant influence of the amount of cellulose on the water absorption was shown.

Resume : Ceramic processing, including shaping of high performance materials and coatings 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. 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 ceramics will be discussed. The authors elaborated the synthesis route of acrylic derivatives of saccharides, which have many advantages. They are non toxic, water-soluble, inexpensive and renewable materials. The research showed that the synthesized compounds could play multifunctional role in gelcasting of ceramic powders: organic monomers able to polymerize in situ, compounds forming self cross-linked polymeric network without external additives and dispersing agents for selected nanopowders. These studies were supported by the Polish National Science Centre under Grant No. 2013/11/B/ST8/0029 and Warsaw University of Technology.

Resume : Preparation of advanced ceramic materials and coatings requires the use of various organic additives which facilitate shaping process of non-plastic ceramic powders. The organic substances can play the role of dispersing agents which stabilize suspensions, binders which hold particles together, plasticizers which give elasticity, monomers together which activators and initiators of polymerization which allow to create polymeric network around powder particles. These additives are subsequently burned-out during sintering process. They are indispensible in shaping step but must be then eliminated in order to obtain pure ceramic phase. For this reason the knowledge about thermal degradation of organics used, as well as decomposition products, seems to be very important from the application point of view. The thermal analysis has been done on the apparatus coupled with mass spectrometer what allowed to observe what types of gasses are released to the atmosphere during heating. It was possible to determine at what temperature regions harmful gases like N2O, NO2 or SO2 are released from the organics and which additives can be treated as environmentally friendly. Thermal analysis allowed to determine the stability regions of prepared ceramic samples. The project has been financially supported by the Warsaw University of Technology, Faculty of Chemistry.

Resume : In recent years there has been growing demand for microfluidic devices such as ceramic microreactors. The application of ceramic microreactors is expected to have a number of advantages like high heat and mass transfer rate reactions as well as excellent thermal and chemical resistance. Thus, the reaction can be performed under more aggressive conditions with higher yields than it can be achieved with conventional reactors. The ceramic microfluidic devices can be manufactured by combination of tape casting and soft lithography method. In soft lithography and tape casting it is possible to apply the UV curable ceramic dispersion. Such combination allows manufacturing instantly the ceramic material with internal structures such as channels, layer-by-layer without stacking of ceramic tapes and lamination process. In this work a photopolymerization of ceramic dispersions in UV curable monomer was used to manufacture the ceramic microreactor by combination of tape casting and soft lithography technique. The effect of particle size and powder concentration on viscosity, cure depth and relative density were investigated. This work was financially supported by Faculty of Chemistry, Warsaw University of Technology The authors would like to thank BTC Europe GmbH for free samples of Irgacure photoinitiators.

Resume : Bio char based carbon and graphene nano structures are very perspective materials for nanoprofiling and modification of polymer composites reinforced by carbon fibers to be used in space, aviation and automotive applications. In this work the materials obtained from pyrolysis and carbonization of pine chips were studied. Techniques such as X-ray diffraction analysis, Raman spectroscopy and transmission electron microscopy were used for structural and morphological characterization of graphite and multilayer graphene nanoparticles that are formed in the 400 to 600° C temperature range On the base of experiment and data analysis, we concluded that the carbonized product of pine chips by pyrolysis consist of two phases, crystalline and amorphous which is confirmed by Raman. Hence this process can be an effective and cheap way to produce graphite and/or graphene nanosheets. The investigations had been supported by FP7 project FIBRALSPEC.

Resume : Up to date, nanocrystalline diamond (NCD) films are regarded as a new material with a high application potential in electronic devices operating in extreme environments. In Ukraine, the works for the synthesis of NCD films are carried out in National Science Center ?Kharkov Institute of Physics and Technology?; here, the deposition method and corresponding setup for diamond films deposition based on the D-C glow discharge in the crossed E/H fields (chemical vapor deposition) were developed. Optical investigation of these diamond materials are performed in V.Ye. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine. The diamond coatings were deposited from the operation mixture CH4/H2 with addition of N2 in various concentrations. It was ascertained that addition of N2 to the operation gas mixture leads to reduction in the sizes of diamond grains as well as to the substantial decrease in the resistivity of the studied films. The electro-physical data are in good agreement with the changes induced by varying the N2 content in the Raman scattering spectra. The increase in the N2 concentration causes significant lowering the crystalline diamond related peak and increase in the intensity of the peaks related to the sp2-bonded carbon. These changes in the spectra indicate significant disordering the structure of the films and can be associated with a decrease in the sizes of diamond crystalline grains and tendency of NCD film to amorphization.

Resume : Zirconia (zirconium dioxide) is a very perspective material for SOFC anode making due to its good combination of mechanical and electric properties. Despite the widespread use of 8YSZ (8-mol. % Y2O3 – ZrO2) for making of SOFC during a past decade, for today most perspective for low temperature (600-800 °C) composition is considered 10Sc1CeSZ (10 mol.% Sc2O3 - 1 mol.% CeO2 – 89 mol.% ZrO2), as it has higher ionic conductivity. Using ceramic component of increased strength while keeping sufficient ionic conductivity results in enhanced SOFC’s anode efficiency at operating temperatures. The aim of this work was to study the creation patterns of 10Sc1CeSZ – 3.5YSZ (3.5-mol. % Y2O3 – 76.5- mol.% ZrO2) system for application as a ceramic component of the SOFC. For this purpose, the influence of 3.5YSZ content on strength and electrical conductivity of 10Sc1CeSZ –3.5YSZ composite were studied. Methods: SEM, XRD, biaxial bend test, impedance spectroscopy.

Resume : Highly porous ceramics on the basis of biogenic hydroxyapatite (BHA) and glass of the SiO2-CaO-Na2O system have been prepared using a replication techniques for the structure of a polymer template in the temperature range 800–1100 °Ñ. It has been established that decreasing of BHA content from 70 to 50 wt. % leads to the decomposition of BHA and interaction with glass mass, which results in forming such phases as renanit NaCaPO4, calcium silicate phosphate Ca5(PO4)2SiO4, calcium pyrophosphate Ñà2Ð2Î7 and hydroxyapatite Ca5(PO4)3(OH), which was confirmed by IR spectroscopy results. An increase in sintering temperature over 1000 °Ñ causes marked volume shrinkage to 76 % and pore structure transformation from an open into closed type. Samples prepared at 900 °Ñ exhibit optimal structural-mechanical properties. They are characterized by a permeatable structure with a predominant pore size of ~ 125 µm and small volume shrinkage of 9-12 %, which makes it possible to fabricate samples with required shape, size as well as total and open porosity of 78-82 and 76-63 %, respectively, and a compressive strength of 0.9-1.0 ÌPà. Moreover, it was found the significant increase in performance osteogenic activity of stem stromal marrow cells of ilium outside the local foci of inflammation and degenerative lesions of human bone tissue in the presence of glassceramics. The materials obtained are promising for replacement of defective bone tissue in orthopedy and traumatology.

Resume : This work present results of the technological properties of ceramic slurries based on silicon carbide powder. For ceramic slurries preparation SiC F400 powder and binder with nanoparticles of Al2O3 were used. To modification technological parameters two polyacrylic binder were added. Solid content was 62,5 wt.%. Standard industrial parameters like: viscosity, density, temperature and pH were measured every day. For better characterization rheological properties of investigated ceramic slurries dynamic viscosity was done. Tests were taken 96h in laboratory condition. Silicon carbide properties: SEM images, grain size and chemical composition were studied. Obtained results shown that ceramic slurries based on SiC and new polyacrylic binder were stable vs. time and meet the standard industrial requirements. Properties of tested ceramic slurries are promising in further fabrication of ceramic shell moulds. Financial support of Structural Funds in the Operational Programme - Innovative Economy (IE OP) financed from the European Regional Development Fund - Project "Modern material technologies in aerospace industry", No. POIG.01.01.02-00-015/08-00 is gratefully acknowledged.

Resume : This work concerns characterization of ceramic proppants applied in hydraulic fracturing during extraction of shale gas. Propping agents pumped with liquid into the deposit cause cracking of the rock. The role of these materials is to avoid closing of formed pores and to enable facilitated gas migration from deposit. Due to processing requirements and conditions in formations (high pressure and temperature), proppants should be characterized by proper physico- mechanical properties. The investigation relates to properties of five kinds of proppants obtained by the mechanical granulation method. Bulk density, roundness coefficient, porosity, pores size distribution, moisture content, turbidity and solubility in acid were examined. Mechanical strength of proppants was established during subjection to the crush test at increasing stress. Structure and morphology of ceramic pellets were determined by the Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDS) and X-Ray Tomography. The results indicate that composition, grain size distribution and morphology as well have an important influence on their fundamental properties during shale gas permeability through the fracture. Keywords: ceramic proppants, granulation, raw materials, shale gas, hydraulic fracturing Financial support of BLUE GAS Programme 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.

Resume : To examine the tribological characteristics of the friction pairs SHM-SHM under dry friction by butt-to-butt scheme. The test objects were production pieces of SHM, i.e. the composites based on the dense modifications of BNsphalerite: composite 01, composite 10, composite 05-IT. The friction pairs were tested by the following regimes: sliding velocity, m/s: 0.1; 0.2; 0.3; load, N: 350; 450; 650; 850; 2100; 3600; dry friction in air. When testing we determined the friction coefficient. The surface roughness of the SHM before the test was Ra = 0.30-0.50 µm. The tribological characteristics of friction pairs of the same superhard materials have been examined. The SHMs exhibited extreme wear resistance in the friction pairs of the same material. The maximum wear resistance under dry sliding showed friction pair composite 10-to- composite 10. In the friction pair composite 05-IT-to- composite 05-IT under sliding speed of 0.1 m/s the decrease in coefficient of friction from 0.40 to 0.06 was observed with increasing load from 350 N to 3600 N. So, an increase in the load by 10.2 times reduced the coefficient of friction by 6.6 times. SHM surface roughness after testing was Ra = 0.15-0.18 µm. The study of friction surfaces showed that the samples were working in the area of elastic deformation. The tested SHMs in friction pairs under dry friction conditions can be ranked as follows with respect to decrease in friction coefficient: composite 01- composite 05-IT - composite 10.

Resume : Wetting of titanium dioxide with iron triad metals was considered in the present work. At interaction of iron and cobalt containing melts to rutile additional liquid phases forms. Temperatures if its appearance (1650 K for iron and 2100 K for cobalt) are in good correlation to temperatures of FeO and CoO melting. From the X-ray diffraction and SEM investigation for iron case second liquid is eutectic between titanium dioxide and pseudobrookite (Fe3Ti3O10), for cobalt case second liquid is eutectic between titanium dioxide and some of ternary Ti-Co-O compound. In nickel case second liquid phase is not observed because NiO in vacuum decomposes before melting.

Resume : In space conditions the electron-beam welding is perspective method to obtain of seams which have good physical and mechanical properties (in weightlessness the molten metal is held in container by surface tension, which generally decreases when the temperature of experiment is increased). For development of new generation of electron-beam emitter the technology of producing of brazed ceramic-metallic joints with complicated design (form) of the ceramic parts was optimized. The samples of high-voltage insulator for electron-beam emitter were produced for work in microgravity. It was proposed a 3th-layers form of the filler (like a "sandwich"): base (Ag, Cu) / titanium / base (Ag, Cu). Work properties of the brazed joints were studied: the tightness (up to 5 atm), the thermal-cycling stability (40 cycles, Т = 770K - 290K - 770K), the cold endurance (up to 198K).

Resume : Today the problem of protection of various parts for shipbuilding engineering, hydropower equipment, floating oil and gas platforms from the action of aggressive media, including seawater, is very urgent. Therefore the development of composite coatings of the NiTi – MeB2 systems is promising. The intermetallic NiTi is known to preserve high strength, hardness and wear resistance up to 400°C under the conditions of combined cavitation and erosion wear. Additionally, it exhibits high resistance to oxidation and corrosion in alkalis, acids, water and neutral media. The present work is devoted to study of wettability and peculiarities of contact interaction in the NiTi-CrB2 system. The intermetallic NiTi has been shown to wet chromium diboride with formation of wetting angle 10°. The phase and chemical compositions of the products in the interaction zone were analyzed. It was established that the chemical interaction between the initial components results in forming a new phase, namely TiB2. Based on the investigation findings for the contact interaction, chromium diboride was selected as an additive to create a new corrosion resistant composite material on the basis of intermetallic NiTi. The microstructure of the developed composite material of the NiTi-CrB2 system and its behavior in aggressive corrosive media, in particular in seawater, were thoroughly studied.

Resume : At first stage for a number of contacting model pairs: olive, castor oil - glass, paraffined glass; water – glass; paraffined glass; water/ethanol – glass, paraffined glass wetting studies in the air atmosphere were performed by a sessile drop method. Taking into account wetting data obtained for particular contacting pairs at the second stage wetting and spreading peculiarities were studied in dynamics by video filming for liquid (oil) contacting with solid surface (glass, paraffined glass) immersed in another liquid (water, water-ethanol solution) immiscible with the first one and having density equal to that of said solution (thus imitating microgravity/zero-gravity state) - at liquid1-solid-liquid2 interface. The results obtained - in particular different and rather strongly distinguished degrees of wetting and liquid-solid interface movement velocities for some contacting pairs can have practical application e.g. for modeling and studying the processes of purposeful liquid capillary transportation, liquids separation and purification at microgravity conditions and development of appropriate space technologies.

Resume : Regularities in the formation of phase and chemical composition, fine microstructure and mechanical properties of surface layers in D16 aluminum alloy under the UIT in the conditions of quasi-hydrostatic compression of samples in rare gases and liquid nitrogen ambient were studied in this paper. A cyclic character of microhardness change in surface layers of D16 alloy depending on oscillation amplitude of tensions concentrator and time of UIT in an inert environment was revealed, which consists in alternation of work-hardening stages, conditioned by structure and phase transformations, as well as plastification stages due to the development of dissipative processes of dynamic recovering and dynamic recrystallization. Work-hardening (in 2,5 time) of D16 alloy surface by means of UIT in an inert environment is conditioned by modification of dislocation structure, deformation forming of nanocrystal structure, and precipitation of nanosize strengthening S' phases. It is shown the unique possibility of work-hardening of D16 alloy surface (in 5 times) by UIT treatment in the liquid nitrogen ambient, conditioned by synergetic influence of nanostructuring and micro chemical impact processes on aluminum in the process of criodeformation. Cyclic character of changes of micro hardness it is not discovered in this case. The development of dynamic recover processes and the evidences of the dislocation annihilation effect are prevented by deep cooling up to the criotemperatures.

Resume : The tin oxide ceramics have specific optical and electrical properties and a good chemical stability. Such ceramics can used in electronics, electrical engineering, electrochemistry, catalysis, biotechnology, metallurgy, atomic and chemical industries, etc. SnO2 belongs to the important class of transparent conductor oxide materials that combine low electrical resistance with high optical transparency in the visible range of the electromagnetic spectrum. These properties are required for optoelectronic applications, light emitting diodes, electrode materials in solar cells flat panel displays, transparent field effect transistors. The reliable electrical contact can be obtained by brazing technology. The wetting joined materials are important for the development of fillers. In this work the wetting of tin oxide ceramic substrate by liquid metals was investigated at high temperatures both in air and in vacuum. The contact angle of pure Ag on surface of tin oxide was 100 degrees in air and 110 degrees in vacuum. Addition of Cu to Ag-melt in air leads to fall in the wetting angle (up to 14 degrees for alloy with 40 at.% Cu) and to raise of the contact angle (up to 120 degrees for same alloy) in vacuum. The microstructure of the transition zone of metal/ceramic interface was studied. The comparison of the wetting in air of tin oxide and other “classic” oxides was carried out.

Resume : Zirconium oxide stabilized by 3 mol.% yttrium oxide is one of the ceramics materials which is using to dental applications, thermal barrier coatings or as a cutting tool material. The properties of this ceramics include high flexural strength, high fracture toughness, high hardness, wear resistance, low thermal conductivity and corrosion resistance in acid and alkalis. One of the method to change the proprieties of zirconium oxide is incorporating a second-phase reinforcement into ceramics matrix. Titanium is a metal which have a wide application including aerospace, automotive, biomedical and chemical industry. The main proprieties of titanium are high strength-to-weight ratio, excellent corrosion resistance, biocompatibility and low mass-to-volume ratio. The combination of these two materials should create a composite which exhibits enhanced mechanical and thermal properties than the two participating components. This work shows the preliminary analysis of composite from the ZrO2 ? Ti system. The samples were prepared from the nano-size ZrO2 powder stabilized by 3%mol Y2O3 and 10% by volume Ti powder with particle size about 15?m. The samples were formed by spark plasma sintering (SPS). The parameters of SPS process was: in temperature 1350?C, with pressure 20MPa and time 10min, with a heating rate of 100?C/min. All process was lead in an inert atmosphere, in argon. The densities of the green body and sintered ZrO2-Ti composites were determined by Archimedes method. The microstructural characterization was carried out using an x-ray diffraction and a scanning electron microscope (SEM) with EDS analysis. Additionally, the Vickers hardness and fracture toughness were measured. Obtained composite samples have a density about 98-99% of theoretical value. During the process was used a graphite die which can react with mixing powder and in effect, on the surface of samples can appear new compounds like TiC. The SEM observation and EDS analysis confirmed that the Zr and Ti are distributed homogenously in analyzed areas. Moreover, the x-ray diffraction reveal the existence of a new phase Ti2ZrO. Keywords Zirconium oxide, titanium, spark plasma sintering (SPS), composite, cermets Acklowledgements The work was done in frame of the project financed by National Center of Science (NCN), project DEC-2013/11/B/ST8/00309.

Resume : In this paper investigated the structure and phase composition of boron coatings obtained after complex saturation with boron and copper low-carbon steels at applying an external magnetic field (EMF). This method obtaining boron coating allows in 1.5 – 2 times to reduce the period saturation detail and get coatings with high hardness, wear resistance, corrosion resistance. At applying the EMF changing morphology boron layers, needles grains decreases sharply, disappear individually disappear sprouted grain borides in the matrix. Needles boron phases closely adjoin to each other and formed a continuous, homogeneous boron layer thickness is in 2 times higher than the boriding without EMF. Established that the diffusion saturation in boriding mixture during 4 hours without EMF obtain coating thickness is 150 microns, then, as at overlay EMF during 2 hours formed coating thickness is 200 microns; complex saturation with boron and copper during 4 hours without EMF formed coating – 175 microns, then, as at overlay EMF after complex saturation with boron and copper during 2 hours formed boron diffusion phase thickness is 230 microns. At applying EMF in boron layers observed decrease of volume phase FeB and on diffraction patterns taken from the surface of boron coatings recorded the presence of phases FeB and Fe2B, and after complex saturation with boron and copper formed phases FeB, Fe2B and Cu.

Resume : Urea and acetamide based ion-organic melts are environmentally safe, stable, and technologically convenient solvents for refractory and noble metals salts, having low melting point and sufficiently broad "electrochemical window". Au wire electrochemical behavior was studied in eutectics urea-NH4Cl (16.8 mol. %) and acetamide-NH4Cl (11,3 mol. %) melts at 393 and 373 K, respectively. During Au anodic dissolution in urea melt, Au (III) planar complexes are formed, and in acetamide one - presumably Au (III) octahedral ammonia complexes. In both of studied melts, Au (III) complexes irreversible cathodic reduction to metal takes place in diffusion regime in two stages: Au (III)  Au (I)  Au (0). Potentiostatic electrolysis of urea-chloride melt with Au anode resulted in 5 microns thick metal deposit with particle size 50-100 nm. Potentiostatic electrolysis of acetamide-NH4Cl melt with Au anode resulted in gold coating deposition onto substrate with individual particles size 200-300 nm.

Resume : Tungsten silicides have wide variety of industrial applications from protective coatings for constructional materials to alternative semiconductors films for solar panels. Particularly, refractory metals silicides coatings deposited by currentless method from molten salts can help to improve some mechanical and physico-chemical properties of construction materials, namely refractoriness, oxidation resistance, and corrosion resistance. Strongly adherent, continuous, and poreless tungsten disilicide coatings were obtained at the tungsten sample surface from the molten NaCl-KCl (eut.) – NaF (20 mol. %) mixture containing 5 mol. % of Na2SiF6 and 20 mol. % of elementary Si at the 1123 K on air during 16 hours. The SEM of the cross-section slice has shown the obtained WSi2 coating at the tungsten surface. Strong adhesion between the coating and the substrate was shown together with the absence of Kirkendall voids and any intermediate layers usually consisting of low silicides.

Resume : To isolate the tungsten compounds from ores and concentrates, method is commonly used of dissolution in various acids which poor performance and environmental hazards are doubtless. As an alternative method, high-temperature selective extraction (HTSE) can be proposed using non-corrosive chloride-silicate melts NaCl-Na2SiO3.During these melts interaction with tungsten concentrates (wolframite or scheelite), tungsten compounds are transferred into the chloride phase, and iron, manganese, and calcium oxides - into the silicate one.Then, phases are separated by selective decantation. The extraction process is carried out in a silicon carbide crucibles. Charge for HTSE contained in weight %: NaCl - 45,0; Na2SiO3 - 20.0; wolframite - 35.0.Process temperature was 1273-1373 K, duration - 2 h.The liquid halide-tungstate phase was decanted to a separate crucible for further electrolytical isolation of tungsten in the form of nanodispersed powders.

Resume : The film continuity is determined by the ratio of the metal film adhesion and cohesion to the oxide surface. Accordingly, systems with high adhesion and wettability oxides by metals the have been selected. In this work the kinetics of dispersion-coagulation during annealing in vacuum of niobium, hafnium and zirconium nanofilms deposited onto oxide (sapphire, ceramics based on ZrO2) materials was investigated. It was found that these films deposited onto oxides have almost no changes its structure during annealing up to 1400 oC, and under further rise annealing temperature films disintegration process was intensified significantly. This disintegration of films on both oxides has approximately the same character and almost finished as a result of annealing for 20 min with simultaneous coagulation of small film fragments into larger conglomerates. The intensity of niobium films dispersion onto investigated oxides is slightly higher compared to hafnium and zirconium films. This phenomenon can be explained by different affinity for oxygen of these metals. Kinetic curves decay of the investigated nanofilms on mentioned non-metallic substrates have been fitted. The resulting experimental data can be used in practice for development of new technological modes of joining by brazing or pressure welding of metallized nonmetallic materials.

Resume : Due to low raw-material cost, low density, high strength, good wear-resistance, excellent oxidation resistance and sulfurized corrosion resistance, Fe3Al based materials have been attracting a lot of attention for promising industrial applications. As is known, introduction of refractory particles TiC to Fe3Al intermetallic matrix promotes increase of their mechanical characteristics. The mechanical properties and microstructures of Fe?16Al based composites reinforced with 5?15 wt.% TiC ceramic particle, produced by hot forging method, were investigated. The composite was received from a mixture of powders Fe, Al and TiC. During heating of intermetallic compounds Fe3Al synthesis was used. Synthesized samples Fe3Al-TiC was forged at 1150 ?C. The relative density of all the composites was up to 99%. Using the received samples the complex physical and mechanical properties (density, electrical resistivity, bending strenght, fracture toughness, hardness) were researched. The structure of composites and uniformity distribution of TiC in a matrix phase were researched.

Resume : In this work are presented results of the investigation of geometrical shape distortion of blanks made of a tungsten_based alloy (W-Ni-Fe). Blanks are found to undergo a multistage form alter¬ation due to a liquid–phase segregation in the material during its sintering in a multizone continuous fur¬nace. We have found the liquid phase flow in W–Ni–Fe alloys with contains of tungsten 89 % (weight) during their sintering in a variable temper¬ature field. As the tungsten_based alloy is moved through the furnace, the liquid phase migrates via pores from the head portion of the blank towards the tail one, thus resulting in a distorted blank geometry not only in the cross_section but also along the blank length. The head portion of the blank retains almost cylindrical shape, suggesting that the liquid phase in this portion migrates almost uniformly throughout the entire cross_section of the blank, and density of the blank head portion corresponds to that of an alloy with 8 wt % binder versus the preset value of 11 wt %; density of the tail portion corresponds to that of an alloy with 12 wt % binder, with¬out regard to the bead. The different edge effects (in terms of the form alteration and binder content) for the head and tail portions of the blank confirm that the distortion of the blank shape is mostly due to the temper¬ature gradient induced along the length of the blank as it travels through the furnace working area.

Resume : Diamond Like Carbon thin films deposited on Si(100) and quartz substrates by Pulsed Laser Deposition (PLD) technique in vacuum or in methane atmosphere were investigated. The morphology, crystallinity, chemical bonding, hardness, adhesion, thickness and optical constants of the as deposited layers were investigated by Scanning Electron Microscopy, X-ray diffraction, Raman spectroscopy, nanoindentation, “pull-out” and spectroscopic ellipsometry. The deposition gas pressure played a crucial role on films thickness, component layers ratio, structure and mechanical properties. Films synthesized in vacuum were a-C DLC type, while those obtained in methane were categorized as a-C:H DLC type. The deposited films were smooth, amorphous, and consisted of a mixture of sp3-sp2 carbon, with 50-90% sp3 content. Most of the films showed a bilayer structure – a higher density layer at the interface with the substrate and a lower density layer on top, as confirmed by the ellipsometric data analysis. Their density and thickness directly influence the overall mechanical properties of the PLD deposited structures.

Resume : Zirconia-based ceramics are characterized by high strength, fracture toughness, corrosion resistance, bioinertness and are perspective for orthopedic and dental restorative applications. The additive of CeO2 and Al2O3 increases resistance of Y-TZP ceramics to low temperature aging in the living organism environment. The microadditive of СоО provides colour contrast of ceramics. The physicochemical properties of nanocrystalline powders for designing of ceramics in the ZrO2–Y2O3–CeO2–СоО–Al2O3 system after heat treatment in the temperature range from 400 to 1300 °C with different amounts of CoO were investigated. XRD phase analysis, scanning electron microscope and BET measurements were used. It was found that the addition of Al2O3 increased the temperature of phase transformation of metastable F-ZrO2 to T-ZrO2 (F-ZrO2→T-ZrO2) whereas the microadditive of CoO decreased the begining of F-ZrO2→T-ZrO2 phase transformation up to 150 °C in comparison with composites in the ZrO2–Y2O3–CeO2 system. The traces of monoclinic phase of ZrO2 (M-ZrO2) were detected after “aging” of composites in the ZrO2–Y2O3–CeO2–СоО–Al2O3 system under hydrothermal conditions. Since the amount of M-ZrO2 after aging was less than 5 % the designed ceramics resistant to the aging in the humid environments and are perspective for the microstructural design of bioinert implants of various purpose.

Resume : The diffusion saturation of iron-based alloys with nitrogen and carbon is widely used in industry for increasing of strength, hardness, wear and corrosion resistance of metal products operating in extreme environment. Inexhaustible and unrealized potentialities of such treatment are opened when applying it under strain and stress condition. The topical question in this direction is to clarify the diffusion and strengthening mechanisms during chemical-thermal treatment of strained alloys . The structure, phase composition and properties of surface diffusion layers formed in the preliminary deformed alfa-Fe, Fe-Cr, Fe-Ti, Fe-Cr-Ti, Fe-Ni alloys after diffusion saturation with N and C were studied. The diffusion layer is a combination of surface layers of different nitride phases, nanostructured eutectoid layer and a zone of internal saturation (alfa– phase). Deformation considerably effects on the phase formation, structure, microhardness and thickness of nitrided layers. The microhardness test of nitrided layers has discovered the narrow intervals of deformations of 3-8 % and 20-30 % in which the considerable rise (in about 2 times) of microhardness of the surface diffusion layer after nitriding exist. The high microhardness of the diffusion layers results from the nitride phases formation.

Resume : Titanium nitride and TiN-based alloys with high wear and errosion resistance are perspective as coatings for various extreme applications. The most promising method of manufacturing of this types of coatings is ion plasma technology using cathode arc vacuum evaporation. This technology allows to create high ionized plazma flows for various gas atmospheres and vacuum and it essentialy influence upon the processes of synthesis and growth of metal and ceramic compounds on various kinds of substrates. Double and triple compounds of titanium nitride with Al, Cr, Zr additives had been produced using arc-vacuum evaporation on modified unit Bulat -3T. The structure and mechanical properties of these coatings had been investigated. It was shown that the main reason of essential hardness increasing for multilayered compositions is the formation of great number of boundaries between nanolayers and blocking of the moving of linear defects by these boundaries. Thus multilayered condensates have a great advantages in comparison with dopped and undopped single layered coatings

Resume : Measuring mechanical properties of materials is important for design and simulation of materials behaviors and evaluation of their functionality, especially for extreme environments. This work deals with measuring mechanical properties of constructional materials using spherical indentation data. Dimensionless expressions for the contact characteristics: contact load, contact area, mean contact pressure, approach of solids, and mean (over the area of the contact) deformation directed along the applied load are based on the finite element simulations. Approximations for dimensionless contact characteristics are obtained in a wide range of material properties: reduced elastic modulus of contact pair, yield strength of specimen material, work-hardening exponent of material. These approximations are also found for hard materials with low ratio of elastic modulus to yield strength. This approach is applied to constructional materials that behave differently in tension and compression

Resume : The opportunity of forming of nanometer-sized through hole in the metal film by heavy ion with energy from the range of elastic loss domination is theoretically investigated. It is assumed that the following conditions have to be met for origination of through hole: 1) molten channel is formed throughout the film thickness h; 2) the total time of pressure stabilization τs ~ 2R/s and melt ejection from the channel Te~ h(p/2vK)1/2 should not exceed the cooling time tT ~ R2/4κ of the channel with radius R. Here s is the sound velocity, ρ is the mass density, K is the bulk modulus, κ is the phonon diffusivity and v is the specific dilatation of film material during melting. The minimal cross size 2Rmin of the channel providing melt ejection is equal to 16κ/s in order of magnitude. Simulations of cascades of excited atoms generated by Xe+ ions with energy of 200 keV in the gold film of thickness h = 50 nm were performed using package SRIM2008. They have shown the possibility of formation with probability w ~ 0.01 near the ion path through the entire thickness of the film of continuous overheated region satisfying the above criteria. The conclusions are in accordance with the experimental data

Resume : Fire safety of wind power units placed in offshore zones depends essentially upon perfection of the lightning protection system of turbine blades. Since the storm activity in the offshore zones is characterized by multi-vector behavior of lightning strikes, and the length of the blades is large and can exceed 80 meters and more, it becomes apparent that special lightning capture coatings are necessary for reliable work. Knitted and soldered special copper netting molded on the surface of carbon plastic composite during the process of wind blade production had been proposed. Unlike other types of lightning receivers proposed meshed lightning receiver has dissipative properties and ensure not only effective removal of electric charges and heat from lightning place but also decreasing of carbon plastic thermal degradation due to evaporation of low-melting solder and straightening of loops Electric charges trapped on lightning receiver discharged using special earthing tire produced from similar mesh. The results of practical tests of such kind of wind blades had been presented

Resume : Recently the polymers has become an avalanche process, due to their unique properties . Particularly, polyimide materials (type PM-A, kapton H) are are widely used in space technics as a basis thermocontrol coverings of SV, as solar reflectors and aerials, electroinsulation materials, materials of fastening of SV devices and other elements SV. However, because of the complex molecular structure of some questions there is still no clear answer. This is due to the fact that these objects are composed of high molecular weight randomly entangled and intertwined molecules. At various external influences they begin to transform, in some cases forming independent structural formations. For X-ray study of such substances gives typical amorphous bodies X-ray scattering pattern, characterized by short-range order. This paper presents the results of a study by X-ray diffraction, polyimide type PM-A Group V [1] subjected to uniaxial tension (elastic deformation), bulk compression (by cooling to low temperatures) and their joint impact. X-ray diffraction studies were carried out on a DRON-2.0 with Cu-Kα anode and Ni filter system with collimation slits. Measurements were carried out in the angular range 2θ = 4 - 70о. The samples, which conducted the study, is a molecular crystal in which there is no long-range order of the position of the molecules. In all the observed diffraction patterns there is a diffuse halo. The reason for this result is, in first approximation, a linear PM-A A can be explained by different mechanisms of ordering of long molecules under uniaxial and bulk loading.

Resume : In the field of materials engineering, scientists from all over the world are continuously developing new materials for challenging applications in aerospace, medicine, transportation or manufacturing, to mention the most important. Ceramic materials (single- or multiphase) are promising materials to fulfil these applications. On the one hand ceramic materials have many beneficial properties such as high hardness, chemical and temperature resistance or excellent wear resistance. Conversely, properties like fracture toughness, thermal shock resistance or Weibull’s characteristics still need to be improved. One of the methods to further improve properties of ceramic materials is incorporation of nano- and micro- metal particles into their structure. These new materials, named ceramic-metal composites, have shown better behavior in the above mentioned areas, depending on type, size and volume fraction of the particular metal particles. In present work the alumina – tungsten composite was formed by slip casting method. The addition of metal phase causes changes in viscoelastic properties of water-based ceramic slurries what has been examined by Authors. Among particles appears the heteroflocculation effect which results in good adhesion between ceramic and metal phases. The ceramic-metal interaction is crucial for improvement of some properties, like fracture toughness. This work was financially supported by National Science Center of Poland (grant number 2014/13/N/ST5/03438).