EFFECT OF OXIDE DEVITRIFICATION ON OXIDATION-KINETICS OF SIC

The effect of oxide crystallinity on the oxidation rate of silicon car bide was investigated, CVD SiC coupons were oxidized in a clean TGA re actor system at 1300 degrees C initially in flowing oxygen, immediatel y annealed in argon, and then reoxidized, all in situ and without cool ing iso as to preserve oxide integrity), The parabolic rate constants determined for the preoxidation regime (of mainly amorphous oxide film ) and reoxidation regime (of devitrified oxide) were compared, The oxi dation rate decreased by a factor of similar to 30 following full oxid e crystallization induced by the anneal.