Powder production processes and properties
Kasimtsev A.V., Levinsky Yu.V., Zhigunov V.V. Production of Ni-TiN composite powder by nitriding of titanium nickelide
The article presents the experimental data obtained in studying the nitriding process of NiTi intermetallide powder produced in the course of hydride-calcium reduction. The theoretical analysis has shown that the process is proceeding in the external conditions with decomposition of NiTi titanium nickelide through Ni3Ti intermediate phase into titanium nitride and solid solution of titanium in nickel Ni(Ti). It has been found that the nitriding process terminates with formation of the following equilibrium phases: TiN1,0 titanium nitride of stoichiometric composition and nickel, which does not contain practically titanium. A model of the nitriding process describing qualitatively the growth of resulting TiN and Ni phases has been proposed. It allows estimating the time of complete dissolution of titanium nickelide in case of NiTi powder particles of specific size.
Onishchenko D.V., Popovich A.A. Production process of carbon powders for making of anodic materials of lithium-ionic (polymeric) storage batteries
Some forms of carbon (anodic matrices) have been produced from renewable vegetable resources: sprouts of bamboo and sugar cane by pyrolysis in experimental thermal installation at temperature of 1000 °C using mechanosynthesis and investigated.
Theory and processes of powder material forming and sintering
Antonova N.M., Kulinich V.I., Dorofeev V.Yu. Adhesive strength of composite coating with polymeric matrix based on sodium-carboxymethylcellulose with metal extender of aluminum powder
A mechanism to form coagulants from small fractions of aluminum powder on steel surface pattern, which provide adhesion cover strength due to Van der Waals interaction forces, has been proposed for the purpose of explanation of adhesion regularities. The role of plasticizer as a factor, which increases adhesion strength of covers by means of decreasing internal stresses in composite and on the interface of steel surface/cover, was determined.
Self-propagating high-temperature synthesis (SHS)
Levashov E.A., Pogozhev Yu.S., Kudryashov A.E., Rupasov S.I., Levina V.V. Nanoparticle dispersion hardened composite materials based on TiC-Ni for electrospark alloying
The macrokinetic peculiar properties of the combustion process have been studied of mixtures in the TiC-Ni system with additives of nanosized ZrO2, Al2O3, Mo-Al2O3 powders as well as the phase composition, structure, and properties of STIM-2 alloy of 80%TiC-20%Ni composition that was dispersion-hardened. The new materials have been produced by SHS, in particular using the process of power SHS-compacting. The addition of nanosized higher-melting-point components was shown to result in decreasing both combustion temperature (on the average by 300-400 K) and its rate (1,5-2,0 times) as well as in inoculation of synthesis product structure when the average size of carbide grains decreases 1,5-3,0 times. The optimal composition of STIM-2 alloy dispersion-hardened by nanoparticles with addition of composite powder on the basis of molybdenum plated with 0,5 % Al2O3 was found to ensure the high level of physical and mechanical properties.
Levashov E.A., Kurbatkina V.V., Rogachev A.S., Kochetov N.A., Patsera E.I., Sachkova N.V. Peculiar qualities of combustion and structure formation in the Ti-Ta-C system
The macrokinetic peculiar properties of the combustion process have been studied of mixtures in the (100 % - Х)(Ti + 0,5C) +Х(Ta + C) system with varying the mixture parameter (X) and initial temperature (T0) of charge heating. Sharp increase in the combustion rate (Uc) and temperature (Tc) has been found for the compositions having X = 10 and 30 % as a result of proceeding two parallel reactions of titanium and tantalum carbide formation. The Uc(Т0) и Тc(Т0) dependencies are linear for the mixture with Х = 50 %. Using the combustion wave quench hardening, it was found that the primary structure formation in the combustion zone begins with precipitation of submicrometer grains of non-stoichiometric titanium carbide from supersaturated solid solution. The synthesis products are single-phase and represent (Ti,Ta)C titanium-tantalum carbide within investigated range of X parameter. Increase of X results in decreasing (Ti,Ta)C grain size and microhardness as well as in reducing the relative density of compact synthesis products. The kinetics of high-temperature oxidation of (Ti,Ta)C carbide based alloys has been investigated. Ceramics produced at X = 10 % possesses the highest heat-resistance.
High-melting, ceramic and composite materials
Zaitsev A.A., Kurbatkina V.V., Levashov E.A. Peculiar qualities of the effect of nanosized additives on production process and properties of sintered Fe-Co-Cu-Sn alloy
The peculiar qualities of the effect of Al2subO3sub, ZrO2sub, WС and Si3subN4sub nanoparticles on the production process, mechanical and tribological properties of 74%Fe-15%Co-9%Cu-1%Sn alloy being obtained by powder metallurgy have been investigated. Mixing of nanoparticles and alloy powder was carried out in centrifugal mill. Nanoparticles uniformly distributed in mixture are shown to aggravate the compaction processes in case of cold compaction and sintering. The alloy dispersion-hardened by nanoparticles and obtained by hot compacting process is characterized by high mechanical and tribological properties: its wear resistance increases 4 times, hardness by 10-16 HRB, and bending strength by 54 %.
Surface modifying, including by charged beams, photon and plasma fluxes
Ligachyova E.A., Ivanov M.B., Gavrilov N.V., Yemlin D.R., Betsofen S.Ya., Ligachyov A.E., Sokhoreva V.V. The effect of nitrogen ion irradiation on properties of pytolytic graphite
The effect of nitrogen ion irradiation (Е = 30 keV, J =1016-1018 cm-2) on elemental composition, topography of surface, and structure of the surface alloy of pyrolytic graphite has been investigated.
Komarov A.O., Belkin P.N.
The effect of surfactants on characteristics of anodic cementation of structural steels
The effect of isoamyl alcohol additives (under 2 mass. %) to water electrolyte for anodic cementation (10 % ammonium chloride and 10 % glycyl alcohol) on volt-current and volt-temperature characteristics of heating steel-10 specimen of 10 mm in diameter and 10-12 mm long has been investigated. Decrease of current density was found in adding isoamyl alcohol and/or glycyl alcohol into ammonium chloride solution that is explained by deterioration of emission ability of the electrolyte because of decrease in local field strength in the centers of anion emission. Increase of heat portion has been found that is supplied to the anode-specimen at the cost of decrease of density of heat flow from the shell into the electrolyte, as caused by growth of thickness of heat boundary layer in adding into the glycyl alcohol solution. An isoamyl alcohol additive to chloride-glycyl alcohol electrolyte is shown to result in decrease of microhardness of hardened layer from 7,0-8,0 to 5,0-5,5 GPa, presumably because of decrease of carbon potential of the saturated medium - anodic steam-gas shell.
Nano-structured materials and functional coatings
Bulanov V.Ya., Krashaninin V.A., Oglezneva S.A. On process of alloying element homogenization in the Fe-Mo, Fe-Cu, Fe-Cr, Fe-Ni nanosystems depending on temperature and sintering time
The article is devoted to the decision of the major problem of powder materials science - the prediction of structural-phase composition in producing new multicomponent materials by means of mathematical description and creation of the computer software for modeling the binary metal-metal system homogenization processes. The processes of homogenization nanopowders in solid-state transition metal nanosystems such as Fe-Mo, Fe-Cu, Fe-Ni, and Fe-Cr have been investigated. Complex theoretical and experimental researches of homogenization processes in solid-state nanosystems have been carried out; analytical time and temperature dependences of the degree of sintering process homogenization are determined; mutual diffusion coefficients in the systems are calculated; physical and chemical models of homogenization are offered; and the means of computer numerical analysis with visualization of processes being studied are created. The estimation of convergence of used numerical methods has been carried out; the accuracy of calculations is appreciated; and estimate calculations for the considered systems are carried out. The results obtained will allow reducing the quantity of natural experiments in creating new materials with specified properties.
Chronicle
To 70th anniversary of B.S. Mitin
