Densification of SiC f/SiC composite by the multi-step of whisker growing and matrix filling

Abstract

The whisker growing and matrix filling process was applied to reduce the canning effect during the CVI process. Grown whiskers may serve to divide the large natural pores between fibers or bundles and then matrix filling may be efficiently carried out through the modified pore structure. In this study, the multi-step of the in situ whisker growing and matrix filling process were performed to investigate the densification behaviors of SiC f/SiC composite. MTS (CH 3SiCl 3) and H 2 were used as source and diluent gases, respectively. The process cycles were repeated three times. The whisker growth and densification behaviors with the number of the process cycles were evaluated. SiC whiskers were grown in the SiC fiber preforms at the input gas ratio of 60 and the total reaction pressure of 5 Torr. As the number of process cycles increased, the maximum size of the large voids decreased and homogeneity of the voids distributions increased.