Thermal Shock Resistance of SiC/Si-Mo Multilayer Oxidation Protective Coating for Carbon/Carbon Silicon Carbide Composites

Abstract

A SiC/Si-Mo multilayer oxidation protective coating for carbon/ carbon silicon carbide composites was prepared by chemical vapor deposition combined with slurry painting, and its thermal shock resistance between 1673 and 373 K was investigated through cooling the coated samples in boiling water. During the whole test, the coated samples lost weight slowly and steadily and the multilayer coating remained intact, with no spallation or peeling. The weight loss of the coated samples was only 1.97% after 50 cycles, and flexural strength test demonstrated that the residual strength retention rates were 95.73% and 81.61% after 25 and 50 cycles, respectively. So an excellent thermal shock resistance had been observed for the SiC/ Si-Mo multilayer coating and certain pores in the Si-Mo layers were proposed responsible for it.