High‐Temperature Oxidation of Chemically Vapor‐Deposited Silicon Carbide in Wet Oxygen at 1823 to 1923 K

The oxidation of chemically vapor‐deposited SiC in wet O₂ (water vapor partial pressure = 0.01 MPa, total pressure = 0.1 MPa) was examined using a thermogravimetric technique in the temperature range of 1823 to 1923 K. The oxidation kinetics follow a linear‐parabolic relationship over the entire temperature range. The activation energies of linear and parabolic rate constants were 428 and 397 kJ · mol⁻¹, respectively. The results suggested that the rate‐controlling step is a chemical reaction at an SiC/SiO₂ interface in the linear oxidation regime, and the rate‐controlling step is an oxygen diffusion process through the oxide film (cristobalite) in the parabolic oxidation regime.