Korsak L.L., Laptev A.I., Sorokin M.N., Shvyndina N.V. Gravity-centrifugal concentration of micropowders of superhard materials
A study of separating diamond micropowders of 60- 14 m m in size fraction in physical properties (dimension and density) with using gravity-centrifugal separator was carried out. Pulp capacity, rotor speed, and position of supply pipe relative to the drain ring were variable parameters in the study. An inversely proportional dependence of synthetic diamond powder fragmentation size on centrifugal field strength was found. Removal of the feeding checkerwork from the drain ring was found to reduce clogging of the top size with coarse grains, and the optimal distance is 125 mm. A new patent gravity-centrifugal method of synthetic diamond separation was developed on the basis of the studies conducted.
Mineral processing of nonferrous metals
Kulifeev V.K., Vatulin I.I., Tarasov V.P., Miklushevsky V.V. Process of lithium metal production by alumothermal reduction of lithium aluminates
In recent years, lithium and its compounds gained in importance in the present-day technologies, by virtue of the above the production of lithium production is permanently and steadily increasing. Therefore the problems of improving the lithium production processes are now actual ones. The authors' experience on development of processes of its vacuum-thermal production by reduction of lithium alimunates by aluminum is generalized. Variants of the process flowsheets are given for different kinds of lithium-bearing raw material and some types of apparatuses for lithium production are described. A comparative analysis of lithium produced by different methods was carried out – according to the developed processes and with using the technique of lithium chloride melt electrolysis. High cost and ecological effectiveness of the methods being proposed is shown.
Ermilov A.G., Rakova N.N., Evdokimova N.V. The effect of different factors on the final composition of decomposition products of tungsten-bearing metalloorganic mixtures
The effect of initial composition and aging process of tungsten-bearing metalloorganic mixtures, catalyzing additives, composition of gas medium, and the conditions of heat treatment on the conversion of tungsten-bearing metalloorganic mixtures into WC and WC- Co nanocrystalline powders was considered. It was found that carbide phases forming in the process of the heat treatment have the increased reactivity, with the result that carbidizing process is limited by the carbon-containing gas medium decomposition kinetics, and formation of tungsten monocarbide is completed at T = 1000 ° C. A possibility is shown to produce WC and WC- Co nanocrystalline powders with particle size of 50- 100 nm.
Casting Production
Belov V.D., Semyonov V.A., Kharitonov V.I., Kucheryaev S.A. Optimization of the composition and process of AK9M2 alloy preparation being applied in the production of engines at OAO “Zavolzhsky Motor Plant”
Optimal composition of AK9M2 alloy production process was developed. The effect of the composition and melt processing on mechanical and casting properties of AK9M2 alloy was studied.
Metal Forming
Tyurin V.A., Adlivankina M.A. Analysis of pressing process of elongated pure aluminum forged pieces
An analysis of the forged piece pressing process was carried out with application of pure aluminum as material for physical modeling. Workpieces were produced of cast ingot and structure was prepared by special forging and heat treatment. Transformation of coarse grains of the macrostructure of the workpieces during pressing process in 3 die impressions was investigated. Recommendations for improvement of the die improvement were formulated on basis of the data obtained on deformation zones and metal macroflows.
Physical Metallurgy and Heat Treatment
Belov N.A., Zolotorevsky V.S., Cheverikin V.V., Yurina E.A. The effect of nickel on phase composition, strengthening and casting properties of aluminum ATs4Mg alloy
The effect of nickel (no more than 6 %) on the structure, strengthening, and cast properties of Al–4 % Zn–1,5 Mg alloy was studied. Non-equilibrium and equilibrium polythermal sections of Al–4 % Zn–1,5 Mg–Ni alloy were plotted, from which it is follows that optimal nickel concentration amounts to ~ 4 %. It was shown that introduction of such quantity of nickel into the base alloy essentially increases the strength properties with insignificant decrease in ductility.
Aksenov A.A., Prosviryakov A.S., Kudashov D.V., Gershman I.S. Structure and properties of composite materials on basis of the Cu- Cr system produced by mechanical alloying
Structure of composite material (CM) on the basis of the Cu–Cr system produced by mechanical alloying was studied. It was shown that the higher portion of chromium in the CM and the longer treatment time, the more intensive dispersion of the structure and increase in its uniformity. The most dispersive structure was observed in the Cu–50 % Cr CM after treatment for 5–8 h. Size of separate structural components is ~ 20¸ 50 nm. It was established that Cu–(30, 40, 45, 50 %) Cr CMs are characterized by increased hardness at the room and elevated temperatures and comparatively high electroconductivity. Hardness of Cu–50 % Cr CM after 5 h of treatment can reach 622 ± 15 HV at electroconductivity of ~ 10 MS/m.
Powder Materials and Coatings
Panov V.S., Narva V.K. Scientific regulations of controlling the properties of sintered hard alloys (analytical review)
Thermodynamic grounds of refractory carbides addition into WC–Co alloys were carried out. Compositions of solid WC–Ni3Al and TiC–Ni3Al alloys were grounded on the basis of the thermodynamic analysis of solid-melt interaction and partial tetrahedration of the Ni–Ti(W)–Al–C system. The results of testing VA-8 alloy (WC–Ni3Al) are given. Processes of liquid-phase sintering and structure formation of carbidosteels are considered. Physical-chemical factors to be necessarily taken into account for forecasting of structure and properties of carbidosteels are estimated.
Ermilov A.G., Skrylyova E.A. A sequence of heterogeneous reactions in the Ni–CO system at carbonylation
Chemical, differential-thermal, X-ray methods as well as photoelectronic spectroscopy were used for studying a sequence of conversions during reduction of nickel oxide film in the atmosphere of carbon monoxide. It was shown that as-reduced Ni intensively reacts at T = 260 ± 370 ° C with producing nickel carbide Ni3C. The carbide layer being formed can prevent from accessing carbon monoxide to the metal surface and blockade both formation of nickel carbonyl and catalytic decomposition of CO with formation of free carbon that begins only at T > 400 ° C, i.e. above temperature of thermal decomposition of nickel carbide.
Structural Macrokinetics. Self-Propagating High-Temperature Synthesis
Levashov E.A., Kudryashov A.E., Pogozhev Yu.S., Vakaev P.V., Sviridova T.A., Zamulaeva E.I., Milonich S., Todorovich M. Investigation of the effect of pulsed discharge parameters on mass transfer, structure, composition, and properties of electrospark coatings on basis of TiC–NiAl modified by nanodispersed components
The effect of nanosized additions (W, NbC and ZrO2) on mass transfer of new SHS-electrode materials on basis of TiC–NiAl has been studied with varying the parameters of pulsed discharges (energies of unit pulse, frequency, and duration). A complex of investigations related to the properties of coatings obtained by Electrospark Alloying (ESA) (structure, phase composition, thickness, uniformity, surface roughness, microhardness, and heat-resistance) was carried out with OT 4-1 titanium alloy. Optimal energy mode of applying the ESA-coatings with help of new electrodes was developed on “Alier-Metal 2002” universal stand. It was established that introduction of a nanodispersed component into electrode material increases thickness, uniformity, and microhardness of electrospark coatings as compared with the electrode without nanoadditions. It was found that ESA-coatings made of new electrode materials improve heat-resistance and tribological behavior of OT 4-1 titanium alloy.
Surface Engineering. Multifunctional Films. Corrosion and Metal Protection
Shtansky D.V., Glushankova N.A., Bashkova I.A., Kharitonova M.A., Moizhess T.G., Sheveiko A.N., Kiryukhantsev-Korneev F.V., Petrzhik M.I., Levashov E.A., Rossi F. New biocompatible coatings of triboligical purpose for medicine
The present-day state of investigations in the field of promising biomaterials is described. A new approach in principle to designing solid biocompatible thin-film materials is proposed. Its main point is that inorganic admixtures of CaO, ZrO2 and TiO2, improving mechanical and tribological properties of the material as well as its biocompatibility, are introduced in the coatings on the basis of titanium carbide, carbonitride or silicide. This allows us to obtain a new class of solid biocompatible thin-film materials of tribological purpose.
Khokhlov V.V., Rakoch A.G., Magurova Yu.V. Electrochemical model of growth of multilayer oxide films at high-temperature interaction of metals with oxidizing agents
Equivalent schemes of growth of multilayer films on the metallic surfaces were developed within the framework of the electrochemical model of high-temperature oxidation of metals in gaseous medium. It is grounded that transfer of ions of oxidizing agent (metal cations) through the preceding layer decomposes into two parallel processes: chemical transformation of the subsequent layer into the preceding one, and diffusion, migration of reacting components through the subsequent layer. By the example of oxidation of copper and metals of titanium subgroup under different external conditions, it is shown expediency of using the above schemes in order to avoid errors in discussing the empiric kinetic regularities. It is found that they can effectively help in finding the methods of producing films of prescribed phase compositions and functional properties on the surface of metal materials in using the method of high-temperature treatment under adjustable partial pressures of oxidizing agents.
Information
Belevitin V.A. A review of monograph: Vol'khin A.I., Eliseev E.I., Zhukov V.P. (Ed. by E.I. Eliseev) “Blister Copper and Sulfuric Acid”
Chronicle
- Anniversary of Nikolai N. Khavsky, Professor
- German A. Libenson is 70 years old
- Sergey S. Kiparisov
