Crack Formation and Distribution of SiC Coating Prepared by CVD on Carbon/Carbon Composites

Abstract

In order to further study the cracks initiation and distribution mechanism of SiC coating, then optimize the coating structure and composition on surface of C/C composites, CVD method is used to deposit SiC coating on C/C composites and pyrolytic carbon. Through the analysis on the reasons of cracks initiation via SEM, the influence of different kinds of substrates and the toughening of SiC whisker on the cracks initiation and distribution are researched. The results show that the cracks easily form in the area near the defects and sample edge, and the cracks also mainly distribute in the direction which are perpendicular to the first fiber layer. Compared with pyrolytic carbon matrix, cracks on C/C composites matrix are width and numerous, and SiC whisker toughening coating can significantly reduce the number of cracks.