Blasting treatment and chemical vapor deposition of SiC nanowires to enhance the thermal shock resistance of SiC coating for carbon/carbon composites in combustion environment

Abstract

To enhance the thermal shock resistance of SiC coating for carbon/carbon (C/C) composites, blasting treatment of C/C substrate and in-situ growth of SiC nanowires by chemical vapor deposition (CVD) were combined before the preparation of SiC coating. Thermal shock test of the SiC coated C/C composites was conducted under oxyacetylene torch from 1600 °C to room temperature. After 15 thermal cycles, the mass loss of the SiC coated C/C composites with only blasting treatment was up to 2.45%, and the C/C substrate was partially exposed in the oxyacetylene torch. In contrast, the mass loss of the SiC coated C/C composites with blasting treatment and CVD SiC nanowires was only 0.9%. The measurement of coefficients of thermal expansion indicated that the combination of blasting treatment of C/C substrate and CVD SiC nanowires could alleviate the mismatch of thermal expansion coefficient between C/C substrate and SiC coating more efficiently, thus improving the thermal shock resistance of SiC coating in combustion environment.