Antsiferov V.N. Editor in chief’s preface
Powder production processes and properties
Amosov A.P., Akhmetsagirov S.M., Bichurov G.V., Ishchuk A.G., Salnikov M.A. Investigation of parameters of powder raw material for manufacture of hard-alloy teeth of drilling bits
The paper contains the results of investigation of powder raw materials (tungsten, cobalt, cobalt oxide, tungsten carbide) by scanning electron microscopy and X-ray phase analysis. The effect of raw material characteristics on the quality of the end tungsten carbide powder has been discussed.
Theory and processes of powder material forming and sintering
Dorofeev Yu.G., Sergeenko S.N., Selezneva E.A. Powder bronze with activated burden doping
The kinetics of dispersion-agglomeration processes and the regularities in forming sintered powder material based on mechanochemically activated (MCA) burdens have been investigated. The effect of powder distribution milling time, energy requirement for milling process, compact and sintered blank densities, ultimate radial compression strength, and strengthening efficiency in introducing MCA-additives was shown. The technology of powdered antifriction bronze with additives of MCA-burdens including mechanochemical activation of compact rejects, compaction, and sintering has been developed.
Self-propagating high-temperature synthesis (SHS)
Levashov E.A., Rogachev A.S., Epishko Yu.K., Kochetov N.A.Self-propagating high-temperature synthesis of target cathodes in the Ti–Ta–C-Ca3(PO4)2 system for ion-plasma spraying of multifunctional biocompatible nano-structured coatings
The results of investigations related to combustion-mode synthesis of biocompatible compact composites of tantalum-containing cathode-targets (Ti,Ta)Cx + Ca3(PO4)2 produced by the process of power SHS-compaction from the mixture of Ti + Ta + C + Ca3(PO4)2 composition and designed for ion-plasma sputtering of nanostructural biocompatible coatings are given. The effect of tantalum-carbon mixture added into the initial burden mass has been investigated. An analysis of the regularities of phase and structure formation in the synthesized products was carried out. No dependence of combustion rate and temperature on relative portion of Ta + C mixture was a new and important characteristic. Two maximums of heat liberation, which give evidence of parallel and successive chemical reaction of titanium and tantalum carbide formation, were observed on the temperature profiles. The growth of relative portion of Ta + C mixture results in modification of carbide structure, increase in residual porosity, and significant increase in hardness.
High-melting-point, ceramic and composite metallic materials
Lysak V.I., Kuzmin S.V., Bagmutov V.P. Basic physics and spheres of practical application of explosion metal welding
The main kinematical and energetic aspects of forming double- and multilayer compounds during the explosion welding of metals are considered. Location of the main specific areas of the process is shown. The critical energetic limits are established depending on the Astrov criterion. The kinematics of plastic yielding of metal within the weld-affected zone has been studied in the course of explosion welding in different colliding modes and the energetic balance in the system of colliding plates has been analyzed. A new parameter of the explosion welding process – deforming pressure pulse value is proposed. The mathematical model describing the process of accelerating and interacting plates in a multilayer stack in welding according to the simultaneous plating scheme is given. The main spheres of practical application of laminated composites produced by explosion welding are shown.
Porous materials and biomaterials
Antsiferov V.N., Porozova S.E. High-porous cordierite ceramic strength improvement by mechanochemical activation of burden
The effect of preliminary mechanochemical activation of cordierite burden composed of natural raw materials on the strength of high-porous articles produced by polymeric matrix duplicating has been investigated. Differential thermal analysis, X-ray spectrometry, and IR spectrometry showed that the beginning of cordierite synthesis in aqueous medium with Versene doping can be observed in the process of activation, and rutile, which reacts with kaolinite, is formed first of all during dry processing with titanium carbide. In activating the burden in aqueous medium, introduction of Versene is shown to give rise to stable increase of strength with satisfactory quality of cordierite; and addition of titanium carbide intensifies the cordierite synthesis process and provides essential growth of strength of high-porous permeable cordierite ceramics.
Surface modifying, including by charged beams, photon and plasma fluxes
Levashov E.A., Zamulaeva E.I., Kudryashov A.E., Vakaev P.V., Sviridova T.A., Petrzhik M.I. Formation processes, structure and properties of electrospark coatings on Armco iron produced in using nano- and microstructural WC–Cо electrodes
Nanostructural and microstructural electrode materials composed of 92%WC–8%Co were used for application of electrospark coatings onto Armco iron when varying pulse discharge energy within 0,01–1,2 J. Physicochemical processes on the contacting surfaces were considered in operating both types of electrode pairs: in formable coating of cathode substrate and in secondary structure of anode-electrode. Amorphous phase and W2C tungsten semicarbide are found to be the basic phases. In case of nanostructural electrode, the growth of power level above a certain threshold value results in increase of a portion of crystalline phases and formation of the structure consisting of submicrometer W2C/WC grains surrounded by the amorphous matrix. In using microstructural electrode, a portion of amorphous phase in the coatings predominates in all power modes. Application of nanostructural electrodes in electrospark processing of the Armco iron substrates is expedient only at pulse energies < 0,23 J.
Nano-structured materials and functional coatings
Antsiferov V.N., Kameneva A.L. Experimental investigation of morphology of multicomponent nano-structured Ti–Zr–N-based coatings formed by ion-plasma techniques
The purpose of the work is establishment of correlations between the processes of formation by vacuum-arc evaporation or combined methods of nanosized coatings on the basis of Ti–Zr–N and the processes that take place in the surface layers of material of sputtered and evaporated targets. TiZrN coatings were deposited with the help of URMZ.279.048 installation equipped with two arc evaporators and four DC magnetrons. Structure, properties, and morphological features of multicomponent nano-structured coating and target surface geometry were studied using Nanoscan atomic power microscope, CARL ZEISS LEO 1430 VP scanning electron microscope, and scanning tunnel microscope "Umka". Difference in the processes proceeding on the surface of evaporated and sputtered targets was discovered; and their analogy with the processes of multicomponent nano-structured coating formation was found for the first time.
