Influence of mechanical activation of reactive mixtures on the microstructure and properties of SHS-ceramics MoSi2-HfB2-MoB

In this work, the influence of modifications of SHS-process on the microstructure and performance characteristics of composite ceramics MoSi2-HfB2-MoB with two-level structure was studied. Partial texturing of MoSi2 grains in samples obtained by force SHS pressing technology was revealed. The effect of preliminary mechanical activation on the macrokinetic parameters of combustion and on the microstructure of the synthesized ceramics was studied. A significant grinding of the synthesized ceramics grain and an increasing of physical-mechanical properties are achieved by increasing the velocity and lowering the combustion temperature of the activated mixtures. The sample obtained by hot pressing of SHS powder from MA reaction mixture showed the most optimal combination of hardness (19.5 GPa), porosity (0.4%) and oxidation resistance (1.82.10(-6) mg/(cm(2).s)).