Combustion Synthesis of α-Si3N4 with the Participation of Low-Melting-Point Salt Additives

Abstract

We have studied the effect of low-melting-point salt additives on the morphology and phase composition of silicon nitride prepared by combustion synthesis. The additives have been shown to influence the structure formation mechanism. Based on equilibrium compositions calculated for particular synthesis conditions, we have proposed mechanisms underlying the influence of the additives on the structure formation process. The synthesis temperature and additives have been shown to influence the phase composition of the synthesis products. Conditions have been found for the preparation of alpha-silicon nitride powders consisting of equiaxed particles.