Kinetics of synthesis of silicon carbide by carbothermal reduction of silicon dioxide

Carbothermal reduction of silicon dioxide in a flowing stream of inert gas was investigated by weight loss measurements, X-ray diffraction, and scanning electron microscopy. The results obtained indicate that the reaction rate can be increased by increasing either the sample size or reaction temperature. Furthermore, the reaction rate was found to increase on decreasing the inert gas flow rate, Si/C molar ratio, grain size of silicon dioxide or carbon, or the initial bulk density. Empirical equations for the consumption rates of SiO2 and C, as well as the production rate of SiC, were also determined. The results also indicate that Fe2O3 acts as a catalyst on the reaction and that both the amount and the Fe2O3 particle size may change the degree of influence on the reaction. BCT/365. (C) 2000 IoM Communications Ltd.