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This paper studies the morphological and structural changes that occur during the graphitization of synthetic diamond powder (with highly faceted edges) and micropowder during heat treatment in air at temperatures up to 1000°C and in a vacuum at temperatures up to 1600°C. The most developed facets of the original diamond crystals are the octahedral {111} and cubic {100} faces. It is established that graphitization begins from the vertices and edges of crystals. {111} faces are more susceptible to graphitization than {100} faces. The morphological analysis of graphitized diamond AC160 in air helps us to study the kinetics of graphitization: the growth of dendritic graphite crystals and the formation of "graphitization pits" on the surface of diamond facets. It is shown for the first time that graphite of different shapes is formed on different diamond faces at different rates; thus, on the {111} faces graphite forms and grows in the form of triangles, and on the {100} faces, in the form of squares. At a high temperature, the volumetric graphitization of diamond particles is observed, accompanied by their destruction, mainly in the growth stages. [ABSTRACT FROM AUTHOR]

Initial powders of Zr, Al, C and Zr, Al, ZrC were used for the synthesis of MAX phases of the compositions Zr2AlC and Zr3AlC2. The highest content (50.4 vol %) of the MAX phase Zr3AlC2 was obtained using the initial powders Zr/Al/ZrC in the ratio of components 1 : 1.5 : 2 with the addition of 5 vol % of Al. The optimal temperature for the synthesis of a material based on the MAX phase Zr2AlC is 1525°C, and that of the material based on Zr3AlC2—1575°C. The structure of the synthesized MAX materials includes elongated grains of the compositions Zr2AlC and Zr3AlC2, which determines their high strength. Zirconium carbide, as an intermediate phase, is always present in the final products. Due to the considerable evaporation of aluminum, the ZrO2 phase is also present in the synthesis products. Excess aluminum contributes to the maximal formation of Zr2AlC and Zr3AlC2 phases during synthesis. [ABSTRACT FROM AUTHOR]

A complex titanium-silicon carbide of the Ti3SiC2 composition was synthesized using various starting components in a high-temperature furnace at 1400°C for 1 h and by subsequent hot pressing at a temperature of 1350°C and a pressure of 30 MPa for 15 min. The content of Ti3SiC2 was calculated by the Rietveld method, with the Ti:Si:TiC ratio reaching 1:1.2:1.8 98.6 vol.% after hot pressing. The microstructure and phase composition of hot-pressed materials, as well as the physical and mechanical characteristics of sintered and hot-pressed Ti3SiC2-based materials, were studied. [ABSTRACT FROM AUTHOR]

Dense materials based on Si3N4 with oxide additives activating sintering were obtained by reaction and liquid-phase sintering and hot pressing. Their physical and mechanical properties were determined. Porous samples were obtained by semi-dry forming of Si3N4 + Si workpieces followed by reactive sintering in a nitrogen atmosphere. The porosity was controlled by decreasing the Si concentration in the initial charge. The thermal conductivity of the materials was highly dependent on porosity and decreased with increasing temperature. The thermal conductivity of hot-pressed materials decreased from 60 W/(m·K) at room temperature to 35 W/(m·K) at 1200°C, at which temperature the weight gain of the samples was 7 × 10–4 kg/m2. The weight gain of the porous materials increased from 4 × 10–3 kg/m2 with a sample porosity of 32% to 6 × 10–3 kg/m2 with 56% porosity. It was shown that an oxygen impurity was the main reason for the decrease in the thermal conductivity of the Si3N4 ceramics. [ABSTRACT FROM AUTHOR]

This research analyzes the methods for producing silicon nitride and the properties of initial powders. The main methods for obtaining materials based on silicon nitride are described. Liquid-phase sintering and hot pressing were used to develop dense materials based on silicon nitride. As a sintering additive, 3 – 10 wt.% and 5 – 20 wt.% of yttrium-aluminum garnet were used for hot-pressed and sintered materials, respectively. The mechanical properties (modulus of elasticity, bending strength, fracture resistance, and Vickers hardness) of sintered and hot-pressed materials have been studied. Maximum properties were obtained with sintered materials containing 15% oxides and hot-pressed materials containing 10% oxides. [ABSTRACT FROM AUTHOR]

SiC materials are obtained by impregnating a porous workpiece consisting of silicon carbide and carbon with liquid silicon. In the composition of the material, at the stage of preparation of charge compositions, up to 18 vol % SiCf is introduced, reinforcing the material and giving it a high level of mechanical characteristics. With an increase in the fiber content (>10 vol % SiCf), the density decreases and the strength of the material decreases; nevertheless, its crack resistance increases. The maximum value of the critical stress intensity factor is recorded for a material containing 15 vol % SiCf–K1C = 6.0 ± 0.2 MPa m1/2 [ABSTRACT FROM AUTHOR]

A diamond – silicon carbide composite material has been obtained. The reaction-diffusion mechanism of Turing sintering is investigated. The conditions for the growth of SiC grains on diamond particles during formation of the composite are shown. The process of graphitization of diamond particles during reaction sintering has been investigated. The mechanical characteristics of the diamond – silicon carbide composite have been studied. [ABSTRACT FROM AUTHOR]

Dense composite materials Al2O3–SiCw with a whisker volume fraction of up to 30 vol% were formed by the methods of liquid-phase sintering and hot pressing. In the presence of 10 vol % SiCw, the density of liquid-phase sintered and hot-pressed materials is decreased to 97.3 and 98.0% of the theoretical density, respectively. For liquid-phase sintered materials, the compositions Al2O3 20 vol % SiCw have maximum characteristics: σben = 416 ± 15 MPa and K1C = 4.74 ± 0.12 MPa m1/2. The introduction of 30 vol % SiCw impedes active compaction of the materials (ρrel = 89.3% of the theoretical density). For hot-pressed materials, the highest characteristics were determined at 30 vol % SiCw : σben = 774 ± 15 MPa and K1C = 5.94 ± 0.12 MPa m1/2. For higher volume fractions, the strength of the Al2O3–SiCw composite materials decreases. [ABSTRACT FROM AUTHOR]

The chemical processes occurring during the interaction of carbon (diamond) with silicon are experimentally investigated. Thermal analysis of the interaction of diamond with silicon is carried out. This made it possible to determine the mechanism of the synthesis of silicon carbide and subsequent reaction sintering of diamond particles based on Turing's reaction-diffusion process and the formation of a microstructure consisting of triple periodic surfaces of the minimal energy. [ABSTRACT FROM AUTHOR]

Information on the temperature coefficient of linear expansion (TCLE) of materials based on silicon carbide is presented. It is shown that the different polytypes 3C (cubic modification) and 4H and 6H (hexagonal modifications) are characterized by different thermal expansions, the difference between the values of which increases with increasing temperature. The TCLEs of reaction-sintered, liquid-phase-sintered, and hot-pressed silicon carbide materials are determined in the range 20 – 1800°C. [ABSTRACT FROM AUTHOR]

The influence exerted by the conditions of the preliminary synthesis of Si3N4 by nitridation at 1350 and 1400°С and additional high-temperature sintering at 1800 and 1900°С on the properties of reaction-bonded silicon nitride was studied. Secondary silicon nitride (β-Si3N4) formed in the course of nitridation consists of needle-like grains, which reinforce the material and impart to it additional mechanical strength. The microstructure and phase composition of the silicon nitride material at different initial ratios of silicon and silicon nitride were studied. The materials obtained approach liquid-phase-sintered and hot-pressed silicon nitride in the mechanical properties. [ABSTRACT FROM AUTHOR]

A dense composite material in the ZrB2–Si system (1400°C, air atmosphere) was obtained. The structure, phase composition, and basic physical properties (density, porosity, elastic modulus, critical stress intensity factor, Vickers hardness) of heat-resistant materials were studied. [ABSTRACT FROM AUTHOR]

Dense ceramic materials of silicon carbide with high mechanical properties are obtained by reaction sintering. The effect of different dispersed compositions of silicon carbide powders on the microstructure, grain size after sintering, and physical and mechanical properties is shown. [ABSTRACT FROM AUTHOR]

Results from studies on the modification of Nb–Cr–Mo–Si–B composites with Mo chalcogenides are presented. Use of MoS2 and MoSe2 as integral parts of multicomponent oxygen-free compositions was shown to have positive effects due to the formation of highly active elemental Mo species resulting from their dissociation that determined the high heat resistance of coatings formed from them. [ABSTRACT FROM AUTHOR]

Reaction-bonded silicon carbide materials have been produced by infiltrating molten silicon into porous bodies consisting of silicon carbide, carbon black, and tungsten-core silicon carbide fibers. Their microstructure and mechanical properties have been studied as functions of reinforcing fiber content. Their bending strength, hardness, and modulus of elasticity have been shown to drop with increasing fiber content because of the increase in the porosity of the composite. At the same time, the fracture toughness of the composite rises to 5.2 MPa m1/2 as the fiber content is raised to 8%. Thus, the mechanical properties of the composite can be improved by optimizing its microstructure and reinforcing fiber content. [ABSTRACT FROM AUTHOR]

Materials based on Si3N4–BN were obtained by liquid-phase sintering using 20% (by volume) YAG as a sintering agent. Boron nitride powders with hexagonal (h-BN) and turbostratic (t-BN) structure were used to obtain composite materials. Highly amorphous t-BN promotes compaction of the materials with the composition (% by volume) 60 Si3N4 + 20 t-BN + 20 YAG and attainment of the highest physico-mechanical properties: ρ = 2.78 g/cm3; P = 14.5%; Eelas = 92.3 GPa; σb = 161.4 MPa. The chemical resistance of the obtained materials reaches 97.0% and increases in the sequence H2SO4 → HCl → HNO3, which attests intercrystalline corrosion without propagation into the interior of the material. However, the resistance to 48% HF is the lowest because of small cracks in the surface intercrystalline layers and deeper corrosion. [ABSTRACT FROM AUTHOR]

An explanation of the physical nature of the experimentally determined concentration dependences of the electrical conductivity of ceramic composite materials of the SiC–TiN (ZrN) system is proposed. A model of the structure and a method for calculating the electrical conductivity of composite materials, as well as experimental dependences of the electrical conductivity of sintered ceramics of the SiC–TiN(ZrN) system are presented. [ABSTRACT FROM AUTHOR]

The paper offers a review of literature published over the past 15 years concerning liquid-phase sintering of silicon carbide materials with various sintering activating additives. The microstructure and specifics of its formation have been investigated. The dependences of crack resistance, strength, and hardness on the material structure were studied. The relationship between the forming microstructure of the liquid-phase sintered material and its mechanical properties has been analyzed. [ABSTRACT FROM AUTHOR]

A review of the literature is presented, including a description of the crystal structure and morphological features of graphite-like hexagonal boron nitride, as well as the preparation of materials based on it. The mechanical and dielectric properties of pyrolytic, hot-pressed (hexagonal and turbostratic modification) and reactive sintered boron nitride are presented. The positive effect of impregnation of porous samples based on boron nitride with organoboron and organosilicon compounds, followed by pyrolysis, on the level of physicomechanical characteristics is shown. [ABSTRACT FROM AUTHOR]

Dense materials based on silicon carbide were obtained by liquid-phase sintering. The oxides MgO, Y2O3 , and Al2O3 , corresponding to the composition of yttrium-aluminum garnet and the triple eutectic point on the line of binary sections garnet-spinel, were used as the sintering additive. The oxides were deposited on the surface of powder by the SiC method of coprecipitation from a solution of salts. The maximum density (ρrel = 99.5%) was attained on SiC materials which include 20% (by weight) sintering additives consisting of a three-component oxide mixture at temperature 1800°C. [ABSTRACT FROM AUTHOR]

SiC ceramic materials were prepared both by reactive and liquid-phase sintering. Structure was modified during preparation by introducing reinforcing SiC-filaments and by synthesizing grains self-reinforcing the structure. The armor-protection capacity was determined by estimating the bullet penetration delay time. [ABSTRACT FROM AUTHOR]

Porous boron-carbide billets containing different amounts of carbon (0 - 15 wt%) were infiltrated with molten silicon to produce dense materials (ρ = 99.6% of theoretical) from starting B4C powders with d0.5 90 and 12.5 μm. The phase composition and microstructure of the material were studied. A solid solution of boron carbide in silicon was determined to be present. [ABSTRACT FROM AUTHOR]

Porous preforms of B4C + C and B4C + C + Si materials were impregnated by liquid (molten) silicon to obtain high-density product with a relative density of 99.0 % and porosity of 0.9%. Silicon impregnation was carried out by saturating the samples through the pores of the SiC + C sacrificial preforms. This method allows to reduce both the dissolution of boron carbide grains in the silicon solution and the formation of the B12(C, Si, B)3 phase. This reduces the fragility of the product and thereby improves the mechanical characteristics of the B4C ceramics. [ABSTRACT FROM AUTHOR]

The free liquid phase sintering method was applied to obtain dense (relative density 99.5%) materials based on silicon carbide. A eutectic mixture of MgO, Y2O3 and Al2O3 of the composition corresponding to the coexisting garnet - spinel phase curve was used as the sintering agent. In the preparation of the charge powders, the method of chemical deposition from salt solutions was used, that produced eutectic composition oxides uniformly distributed on the silicon carbide powder particles. The materials produced show good mechanical properties: elastic strain energy 410 GPa, flexural strength 680 MPa, KIc = 6.0 MPa·m1/2, HV 21.5 GPa, the values of which are close to the corresponding indices for the hot-pressed carbide-silicon materials. [ABSTRACT FROM AUTHOR]

The melting (decomposition) point for AlMgB14 aluminum magnesium boride containing alumomagnesium spinel as an impurity (5.5 wt %) is experimentally evaluated. The melting is accompanied by the release to the gas phase. The decomposition process covers the temperature range of (2400–2573) ± 30 K. A partial loss of Mg is observed at 2073 K. The structure and element composition of crystallized objects are also studied. [ABSTRACT FROM AUTHOR]

A composite material based on the B4C–SiC system with different initial carbon contents was obtained by reaction sintering (impregnation of a porous billet with liquid silicon). Carbon reacted with silicon to form a secondary silicon carbide that filled the space in the porous workpiece until a monolithic material was obtained. Boron carbide acted as the source of carbon if it was initially absent or its content was low. The obtained materials had the following characteristics: bending strength up to 320 MPa, density up to 2.85 g/cm3, microhardness up to 30 GPa. [ABSTRACT FROM AUTHOR]

The mechanism of sintering and the particulars of structure formation in liquid-phase-sintered silicon carbide and sintered silicon nitride were studied. The formation of the structure core (SiC or Si 3Ni 4 grains) – boundary layer (SiC oxide or SiAlON) – intergrain phase (oxides) was recorded. [ABSTRACT FROM AUTHOR]

In the title section in the authors list Previslov should be replaced by Perevislov. [ABSTRACT FROM AUTHOR]

The system xBa(PO3)2·(99 – x)(AlF3–BaF2–CaF2–MgF2–SrF2)–1NdF3, where x = 2, 5, 10, 15, 20, 30, and 40 mol %, is considered. The dependences of the thermal coefficient of linear expansion, Tg, Tx. Tx–Tg, HV, and K1C on the concentration of Ba(PO3)2 are determined. It is found that an increase in the concentration of Ba(PO3)2 with the uniform replacement of the fluoride component leads to a decrease in the thermal coefficient of linear expansion, an increase in the glass transition temperature and crystallization, and a broadening of the interval Tx–Tg. It is shown that an increase in Ba(PO3)2 in the glass leads to an increase in microhardness HV and fracture toughness K1C of the glasses. The main thermomechanical characteristics of the studied glasses are compared with those of their commercial analogs. [ABSTRACT FROM AUTHOR]

A criterion for the selection of materials to protect against the mechanical dynamic loading is proposed and substantiated. The mechanisms of the fracture of brittle ceramic materials that are widely used in structures that prevent penetration and are very common in practice are discussed. Unlike other estimates, the proposed formula is based on the physical principle of comparing the total energies of loading and obstacles, and is in good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

Various mixtures of initial Ti/Si/C, Ti/Si/TiC, Ti/SiC/C, Ti/SiC/TiC, Ti/TiSi2/TiC, and TiH2/SiC/C powders were used to synthesize Ti3SiC2 by sintering at 1300 and 1400°C for 1 – 5 h. Ti/Si/TiC and Ti/TiSi2/TiC powders were best for synthesizing Ti3SiC2. The amount of synthesized Ti3SiC2 reached 98.3 and 90.3 vol% at a sintering temperature of 1400°C for 1 h. Ti3SiC2 was synthesized and grew in the form of elongated grains. The influence of the sintering time and temperature on formation of the MAX-phase Ti3SiC2 from the initial Ti/Si/C powders was determined. TiC and a small amount of SiC were always present as intermediate phases in the final products. An excess of Si contributed to the highest formation of Ti3SiC2. [ABSTRACT FROM AUTHOR]

The influence of nanosized ZrO2 and Al2O3 particles on the physicomechanical properties (elasticity modulus, flexural strength, microhardness), phase composition, and microstructure of materials based on Si–B4C–ZrB2 was studied. A borosilicate glass-forming melt that encapsulated the starting components was obtained by reactive heat treatment in air in an electric furnace [1]. Gradient materials in which the glass-ceramic surface layer protected underlying layers from oxidation were obtained. This approach could be used to obtain protective coatings for carbon materials. The additives were shown to improve the mechanical properties of composite materials. [ABSTRACT FROM AUTHOR]

The use of high-modulus ceramic materials under conditions simulating the screen protection of space objects from damage by fragments of space man-made debris is considered. The introduction of an aluminum jet at a speed of ~ 10 km/s into an aluminum barrier located behind brittle material screens was experimentally studied. A comparative analysis of the parameters of the residual cavity in the barrier made it possible to reveal the effect of the structural rearrangement of the ceramic material on the effectiveness of screen protection. [ABSTRACT FROM AUTHOR]

For the first time, a new ceramic "Ideal," a diamond-silicon carbide composite obtained in the reaction-diffusion Turing process, which makes it possible to obtain materials with the optimal set of physical and mechanical properties, is studied. An elastic-brittle fracture related to the propagation of a shock wave in a two-component system is noted. The dynamic elastic limit, determined by the properties of silicon carbide, is found to be 13.4 GPa. Its dynamic elastic limit and spall strength in the region of the elastic deformation are measured. The impact compressibility of ceramics up to a pressure of 625 GPa is determined. [ABSTRACT FROM AUTHOR]

In this paper, a new diamond–silicon carbide ceramic composite material—Ideal—is studied and its mechanical characteristics are determined. For the first time, a comprehensive determination of Poisson's ratio, shear modulus, bulk modulus, and transverse sound velocity is carried out. Poisson's ratio is in the region of 0.008 to 0.01, which, in turn, indicates the absolutely brittle nature of the failure of the Ideal ceramic under loading. The criteria that allow evaluating different materials used for body armor are calculated. [ABSTRACT FROM AUTHOR]

The possibility of producing geometrically complex mechanical-engineering products based on reaction-sintered silicon carbide using two methods was investigated — mechanical processing of polymerized workpieces before sintering and molding by hot slip casting under pressure. The resulting silicon carbide ceramic materials are characterized by low density of the order of 3.04 – 3.07 g/cm3, porosity ≤ 1%, and bending strength 320 – 360 MPa. Materials based on silicon carbide modified with boron carbide have density 2.72 g/cm3, porosity about 1%, and bending strength of 280 MPa. [ABSTRACT FROM AUTHOR]

The influence of the synthesis temperature on the phase composition, size distribution, and morphology of AlMgB14 particles, obtained by direct interaction of powders of elementary Al, Mg, and B with the addition of free carbon in vacuum 10 – 2 Pa at 1200 – 1400°C, was studied. The synthesized powders were analyzed by means of x-ray diffraction, SEM, EDX, and laser diffraction. The highest mass content of the main phase AlMgB14 (94%) was obtained at synthesis temperature 1200 – 1300°C with 1 h soaking. Impurity MgAl2O4 as well as magnesium-depleted spinel and AlB12 were recorded at soaking temperature above 1300°C. [ABSTRACT FROM AUTHOR]

Ceramic materials based on B4C–SiC are obtained by using the method of hot slip casting followed by reaction sintering (impregnation with liquid silicon). Composite ceramic samples are characterized by low density and porosity, and have strong mechanical characteristics. The microstructure of the obtained material is studied, and the uniformity of the distribution of boron carbide and silicon carbide particles in the structure of ceramic materials is demonstrated. [ABSTRACT FROM AUTHOR]

The high-temperature strength properties of silicon carbide-based ceramic materials reaction-sintered in air and vacuum are proved by experimental data. The ultimate bending strength of pressed and cast ceramic material samples at temperatures up to 1400°C was measured as a criterion. High-temperature tests demonstrate the guaranteed strength of ceramics above 100 MPa. An example of the manufacture of a complex shaped ceramic product using the hot slip casting processing under pressure into additive water-soluble forms is given. An approval of the combined technology makes it possible to manufacture bladed ceramic elements with a thickness of about 1 mm. [ABSTRACT FROM AUTHOR]

Si3N4-based ceramics have been produced by hot pressing in the temperature range 1550–1650°C using α-Si3N4 starting powder and CaO–Al2O3 (48 : 52 wt %) sintering aids. The powders and the ceramics have been characterized by dilatometry, scanning electron microscopy, and X-ray diffraction, and we have measured the microhardness and density of the ceramic samples. The results demonstrate that the sintering aid reacted with Si3N4 to form Ca-α-SiAlON. At 40 wt % sintering aids, all of the silicon nitride was converted into Ca-α-SiAlON. We have clarified general trends in the effect of the amount of sintering aids on the properties of the ceramic samples. [ABSTRACT FROM AUTHOR]

This paper studies the resistance to oxidation of various grades of commercial diamond powders. The kinetics of diamond oxidation in air is studied by optical and electron microscopy, as well as X-ray microscopic and thermal analysis. The relationship between the size of diamond grains, their morphology, and their impurity composition with temperature, heat release, and the rate of the process is studied. It is established that the main factor affecting the behavior of diamond during its combustion is the type of impurities present in the powders, followed by the grain size and its morphology. A complex multistage nature of the oxidation process is discovered. [ABSTRACT FROM AUTHOR]

The results of studying the structure of additively manufactured permanent magnets based on AlNiCo35 alloy are presented. Structural features are identified with optical and electron microscopy, and the phase composition is determined with X-ray diffractometry. The possibility of manufacturing magnets by selective laser melting of metal powder is shown. [ABSTRACT FROM AUTHOR]

Diamond–SiC composite materials were obtained by impregnation with gaseous and liquid Si. The mechanisms of the impregnation and consolidation of the diamond–silicon carbide composites were studied. The effect of the Turing reaction–diffusion mechanism on the sintering of the diamond–SiC materials, the formation of the microstructure, and the mechanical properties was shown for the first time. [ABSTRACT FROM AUTHOR]

Results of theoretical and practical studies of the formation of functional ceramic coatings by a method of microspark oxidation in an electrolyte based on boric acid are presented. Good chemical stability of an oxide film in the borate electrolyte is noted, It is shown that treatment of an aluminum surface for 2.5 h at a current density of 5 A/dm2 leads to formation of a ceramic coating with porosity of not more than 3% and thickness of about 50 μm impregnated with corundum. The main factors affecting borate electrolyte durability in the process of aluminum microspark oxidation are determined. [ABSTRACT FROM AUTHOR]

Dense silicon carbide-based ceramic composites reinforced with SiCf fiber have been produced by hot pressing at a temperature of 1850°C. The reinforcing agent used was silicon carbide fiber produced by siliciding carbon cloth with SiO vapor. It has been shown that raising fiber content from 1 to 7 wt % increases the density, bending strength, and fracture toughness of the material, which reach ρ = 3.20 ± 0.01 g/cm3, δb = 450 ± 26 MPa, KIс = 5.6 ± 0.1 MPa m1/2 at 7 wt % SiC fiber. [ABSTRACT FROM AUTHOR]

Si3N4–TiN ceramic composites have been produced by hot-pressing mixtures of silicon nitride and metallic titanium powders at temperatures from 1600 to 1800°C in a nitrogen atmosphere. We have examined the influence of the concentration and morphology of metallic Ti particles in the starting mixture and synthesis conditions on the microstructure, phase composition, and mechanical strength of the Si3N4–TiN ceramic composites. The results demonstrate that the sintering process ensures complete titanium nitridation, leading to the formation of a nonstoichiometric titanium nitride with the composition TiN0.9. The Si3N4–TiN composites prepared from the mixtures containing 5–30 wt % Ti have densities in the range 3.02–3.41 g/cm3, water absorption from 0.01 to 0.14%, open porosity from 0.03 to 0.44%, and bending strength from 250 to 584 MPa. The Si3N4–TiN ceramics prepared using calcium aluminates as sintering aids consist of dense intergrowths of silicon nitride crystallites, which ensures increased strength of the materials. Moreover, the samples containing 25–30 wt % TiN offer high electrical conductivity. [ABSTRACT FROM AUTHOR]

Abstract—: This paper presents dilatometric analysis data for the sintering of off-the-shelf molybdenum disilicide (MoSi2) powder prepared by magnesiothermic synthesis. We have obtained continuous shrinkage curves for MoSi2 powder compacts with an initial relative density of 70% at different heating rates: 5, 10, 20, and 30°C/min. From a quantitative analysis of densification curves for the compacts, the activation energy for the initial stage of sintering has been determined to be Q = 695 kJ/mol. It has been shown that the dominant process in the initial stage of MoSi2 powder sintering is volume diffusion from grain boundaries and surfaces. [ABSTRACT FROM AUTHOR]

Results are given for development of technology for electrolytic deposition of protective and electrical insulating ceramic coatings. The technology developed consists of combining microarc oxidation with imposition of excess pressure in a closed autoclave with the introduction of nanoparticles into the coating formation probe. [ABSTRACT FROM AUTHOR]

This work reveals that addition of 4–6 wt.% of aluminum powder to the composition of a hard alloy powder provides surfacing of high-quality coatings without pores, cracks, and other defects. At the same time, aluminum is a strong deoxidizer and a nitride forming element, which permits use of nitrogen, compressed air, and hot hydrocarbons instead of argon as transporting gases. It is shown that the use of aluminum powder reduces the loss of alloying elements, increases the hardness of deposited coatings by 3–5 НRС, and also significantly reduces the cost of plasma surfacing due to a reduction in argon consumption. [ABSTRACT FROM AUTHOR]