Producing Nanodispersed Composite Nitride Powders by Nitriding of Recursors

Abstract

Highly dispersed and nanodispersed composite powders based on Si₃N₄–TiN, Si₃N₄–CrN, BN–AlN, and BN–Si₃N₄ non-metallic nitrides are produced by nitriding of precursors. Main criteria for selecting precursors for the synthesis of these powders are determined. Nitriding features are analyzed on the basis of the powders of TiSi₂, CrSi₂, B₄Si, and AlB₂ precursors both in the mechanically activated and non-activated conditions. It is established that the mechanical activation of precursors substantially decreases the temperature of nitride formation and enables synthesizing nanodispersed composite nitride powders with a particle size of 30–70 nm. In comparison with the specimens produced from the powders synthesized by conventional techniques, the specimens produced by hot pressing and spark plasma sintering possess a highly dispersed microstructure with a uniform distribution of phases and advanced physical and mechanical properties.