Synthesis of well-dispersed β-Si3N4 with equiaxed structures using carbothermal reduction–nitridation method

Well-dispersed β-Si3N4 powders with a novel equiaxed structure and eminent crystal integrity were prepared by carbothermal reduction–nitridation (CRN) strategy with the assistance of CaF2 additive. The growth mechanism of Si3N4 particles in the CRN process was elucidated. It is proposed that the liquid phase formed by SiO2 and CaF2 additive is crucial to the formation of equiaxed β-Si3N4, and with an appropriate content of CaF2, Si3N4 powders with pure β phase, superior dispersity and crystal integrity can be obtained. © 2017 The American Ceramic Society