STUDY OF THE PROPERTIES OF DIFFUSION-HARDENING COMPOSITE SOLDERS MODIFIED WITH A Ti-Mo POWDER MIXTURE

В статье обсуждается возможность регулирования свойств диффузионнотвердеющего припоя на основе легкоплавких сплавов галлий-олово, галлий-индийолово, галлий-олово-цинк и твердой компоненты состоящей из порошка сплава медь-олово посредством введения смеси инертных порошков металлического титана и молибдена после термической обработки при различных температурах. Оценена микротвердость и термическая устойчивость композиционных диффузионнотвердеющих припоев. Показано, что термическая обработка при более высоких температурах способствует переходу припоя в равновесное состояние, при этом происходит резкое увеличение твердости. Методом рентгенофазового анализа определены образующиеся в результате диффузионного твердения фазы. Показано, что при различных температурах обработки образуются разные фазы - наноразмерные интерметаллические соединения. За счет небольших добавок наполнителей, инертных или слабовзаимодействующих с галлием, но хорошо им смачиваемых, характеристики диффузионно-твердеющего припоя значительно улучшаются. The article discusses the possibility of regulating the properties of diffusion-hardening solder based on low-melted gallium-tin, gallium-indium-tin, gallium-tin-zinc alloys and a solid component consisting of a copper-tin alloy powder by introducing a mixture of inert powders of metallic titanium and molybdenum after the heat treatment at various temperatures. The microhardness and thermal stability of composite diffusion-hardening solders are evaluated. It is shown that the heat treatment at higher temperatures contributes to the transition of the solder to an equilibrium state, while a sharp increase in hardness occurs. The phases formed as a result of diffusion hardening were determined by the method of X-ray phase analysis. It is shown that at different processing temperatures, different phases are formed - nanoscale intermetallic compounds. Due to small additives of fillers that are inert or weakly interacting with gallium, but are well wetted by it, the characteristics of the diffusion-hardening solder are significantly improved.

Modeling of protective plasma spray ceramic coating made of clad powder mixture

To solve the problem of increasing the adhesive-cohesive strength of plasma multifunctional coatings used to protect parts of power and mechanical engineering equipment components from wear and corrosion, a ceramic coating of the “Al2O3 - Ni” system, obtained from a powder mixture based on corundum clad with nickel, is proposed for use and studied. The coating was applied by high-energy plasma powder deposition (on the “Thermoplasma-50” installation) to the intermetallic sublayer of the “Ni-Co-Cr-Al-Y” system. The aim of this work was to study the micro structure and phase composition of the powder mixture of oxide ceramics clad with a refractory metal component (nickel), as well as the plasma coating formed from this powder material. According to the results of the research, it was found that the powder mixture clad with nickel has a multiphase composition (Ni+l-Al2O3+r-Al2O3), a spherical morphology of particles. From this powder material, a coating with a phase composition (Ni+L -Al2O3+J ’-L J u Ll) is formed, characterized by a layered microstructure with a columnar structure of oxide grains and nickel interlayers. The coating has high hardness and adhesive-cohesive strength, low coefficient of friction and is recommended for protection against wear of energy and mechanical engineering parts.

SHOCK-WAVE INITIATION OF SYNTHESIS IN NI-AL POWDER MIXTURE INSIDE TITANIUM MATRIX

This study presents the results of studying the effect of shock-wave loading on the initiation of synthesis in Ni-Al powder mixture inside titanium matrix. X-ray phase analysis (XRD) and measurement of the microhardness of the intermetallic layer showed that this layer consists of a monophase product NiAl, which is formed directly during explosive loading at a given impact velocity of the plate. Thus, the use of shock-wave loading made it possible to obtain a layered material with a strengthening intermetallic layer. The results obtained are promising for the development of new structural materials with special performance properties.