Oxidation of Cr3Si-Cr7C3/SiC/SiC Coated C/SiC Composite in Wet Air

Abstract

Oxidation behavior of a Cr3Si-Cr7C3/SiC/SiC coated C/SiC composite was investigated in wet air at 700, 900 and 1300 ºC under 1 atm with a gas velocity of 3.0 cm s-1, and compared with that of a SiC/SiC/SiC coated C/SiC composite. The wet oxidation produced phases on the Cr3Si-Cr7C3/SiC/SiC coating were Cr2O3 at 700 and 900 ºC, and Cr2O3 and SiO2 at 1300 ºC. The Cr3Si-Cr7C3/SiC/SiC coating showed enhanced protection against wet oxidation compared to the SiC/SiC/SiC coating. After oxidation for 10 h, the Cr3Si-Cr7C3/SiC/SiC coated composites showed nearly the same failure behavior and residual flexural strength as the as-received composites.