Oxidation kinetics of hot-pressed silicon carbide

The oxidation of silicon carbide, hot-pressed with ∼ 4 wt % Al2O3, in 1 atm dry oxygen follows classical parabolic behaviour with an activation energy of 481 kJ mol−1 in the temperature range 1200 to 1400° C. The oxide film consists predominantly of cristobalite and a glassy phase in which additive (Al) and various impurity elements (Fe, Na, K, etc) concentrate. The desorption of CO(g) from the SiC/SiO2 interface appears to be oxidation rate controlling.