International Journal of Self-Propagating High-Temperature Synthesis最新文献

Selective laser melting (SLM) was first used to deposit products made of SHS-produced intermetallic alloy Ti₂₀Al₃Si₉ powder on the Ti substrate. It was shown that formed Ti₂₀Al₃Si₉ alloy/Ti substrate composites have a strong bond. The influence of SLM parameters for processing SHS-produced powder on microstructure and phase composition of clad samples was studies.

Porous ceramic materials were sintered from fine SiC filler powder produced via SHS with binders SiO₂ and MgO at temperatures of 800–1300°C. The effect of sintering temperature on the properties of the resulting ceramics such as pore size, open porosity, bending strength, and pure water permeability was investigated. SiC-based membrane rejected completely solid SiC particles with D₅₀ = 0.5 μm while maintaining stable permeability and physical and mechanical characteristics after repeated filtration/regeneration cycles.

MgAlON ceramics were prepared by combined use of self-propagating high-temperature synthesis of Al + Al₂O₃ + MgO + Mg(ClO₄)₂ mixtures doped with sintering agent LiF, CaCO₃ or La₂O₃ + Y₂O₃ + MgO and pressureless sintering. The effect of additives on the combustion process and phase formation of synthesized products, as well as their subsequent sintering was studied. Introduction of 10 wt % CaCO₃ was shown to lower the combustion temperature followed by stopping the combustion front. It was revealed that the density of sintered ceramic materials reaches 90% of the theoretical value. The sintered sample prepared by doping with 0.6 wt % CaCO₃ was found to possess the highest density (3.3 g/cm³) and light transmittance (16%).

Cast Mo–Nb–Ta–(Cr,V,Zr,Hf) refractory high-entropy alloys were first prepared via gravity-assisted SHS metallurgy. It was shown that the ingots crystallize from the liquid state, in which a homogeneous distribution of constituting elements is provided. The phase composition of synthesized RHEA ingots was revealed to be doped component dependent. Combined reduction of metals of V (Nb, Ta, V) and VI (Cr, Mo) groups formed single-phase alloys with a bcc crystal structure. MoNbTaCr alloys doped with Zr or Hf having hexagonal crystal structure were found to consist of fcc and hcp phases in addition to bcc solid solution.

Cu₂Se thermoelectric compound containing up to 5 wt % SiC was prepared via self-propagating high-temperature synthesis. Doping SiC was shown to improve the thermoelectric properties and get 20% increase in the electrical conductivity and 60% increase in the Seebeck coefficient. The thermoelectric power factor of Cu₂Se–5 wt % SiC was found to be 14.4 μW cm^–1 K^–2 at 900 K, which is 3 times higher than that of Cu₂Se.

V₂AlC powder was prepared through self-propagating high-temperature synthesis of VO₂/Mg/Al/C mixture in molten NaCl followed by leaching in dilute hydrochloric acid. The synthesized product included V₂AlC, vanadium aluminides and carbides, as well as MgO and MgAl₂O₄. The phase composition was found to be magnesium and carbon content dependent. Optimum component ratios and acid leaching conditions were determined for the successful synthesis of V₂AlC MAX phase.

The work investigated the modes of synthesis of titanium carbide with a nichrome binder from granular charges containing up to 30 wt % nichrome or a mixture of nickel and chromium powders taken in the same ratio as in the alloy. Using the conditions for the transition of combustion from conductive to convective mode, the impurity gas content in the studied mixtures was quantitatively assessed. It was shown that for mixtures of 0.6-mm granules, a safe conductive synthesis mode is realized. For charge of 1.7-mm granules, if a mixture of Ni and Cr powders was added to the initial sample, the convective combustion mode took place when Ti + C content was more than 90 wt %. When adding nichrome powder, the convective mode was caused by more than 80 wt % of Ti + C. Replacing the nichrome powder in the initial granular charge with mixture of Ni and Cr powders did not change the phase composition of the combustion products.