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

Oxidation behavior of a Cr 3 Si-Cr 7 C 3 /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 Cr 3 Si-Cr 7 C 3 /SiC/SiC coating were Cr 2 O 3 at 700 and 900 ºC, and Cr 2 O 3 and SiO 2 at 1300 ºC. The Cr 3 Si-Cr 7 C 3 /SiC/SiC coating showed enhanced protection against wet oxidation compared to the SiC/SiC/SiC coating. After oxidation for 10 h, the Cr 3 Si-Cr 7 C 3 /SiC/SiC coated composites showed nearly the same failure behavior and residual flexural strength as the as-received composites.