Influence of different types of the boron on the processes of TiN—TiB₂ composition synthesis by the method of reactionary electric discharge sintering

Abstract

The brown boron powder of (Merck, Germany) had higher content of magnesium and enhanced specific surface as compared to the black boron powder (Dzerzhinsk, Russia), however it have resulted in distinctions in properties of the ground mixtures. The boron was in the amorphous state, and В₂О₃ was in relatively coarse-crystalline state in black powder. Predominance of amorphous phase and higher initial purity of black powder of the boron resulted in its enhanced reactivity. Titanium diboride synthesized from the black boron possessed higher conductivity. It caused the shrinkage-rate increase at reactionary electric discharge sintering and, thus, obtaining of enhanced density of the sintered TiN—TiB₂ composites and higher mechanical properties.