Effect of oxygen partial pressure on the high-temperature oxidation of CVD SiC

The oxidation behavior of chemically vapor-deposited silicon carbide (CVD SiC) was studied at 1670-2010 K in O-2-Ar and CO2-Ar. The oxidation kinetics in O-2-Ar was parabolic or linear parabolic, and was parabolic in CO2-Ar. The activation energy for the parabolic rate constants (k(p)) was 210-220 kJ/mol in O-2-Ar, and was 290-300 KJ/mol in CO2-Ar. The oxygen partial pressure (P-O2) dependence of k(p) was expressed as k(p) proportional to (P-O2)(n), where n = 0.08-0.13 and 0.37-0.53 in O-2-Ar and CO2-Ar, respectively. Bubbles were formed at more than 1985 K and PO2 > 5 kPa. The bubble formation temperature decreased with decreasing P-O2 at P-O2 < 5 kPa. © 2001 Elsevier Science Ltd. All rights reserved.