Calculated influences of starting materials composition on carbothermal nitridation synthesis of silicon nitride/silicon carbide composite powders

摘要

Equilibrium phase composition at 1 atm total pressure is quantitatively calculated as the function of starting materials composition for carbothermal nitridation synthesis of Si3N4/SiC composite powders. N2 flow is simulated by the N2 amount in the starting materials. At low starting N2 content (molar ratio N2/SiO2 ≤ 100), Si3N4 and SiC can not exist in equilibrium at the same temperature. At higher starting N2 content, the Si3N4-SiC coexisting temperature range appears above 1760 K. The upper limit of the temperature range becomes higher with increasing starting N2 content. Starting carbon content affects the composition in the equilibrium powder products. The calculation results are compared with experiments.