Fabrication of SiC_f/SiC Composite by Chemical Vapor Infiltration

Abstract

Among several fabrication processes of SiC f /SiC composites, the chemical vapor infiltration (CVI) process has attractive advantages in manufacturing complex net-or near-net-shape components at relatively low temperatures, easily controlling the microstructure of the matrix and obtaining the highest SiC purity level. However, it has disadvantages in that the ratio of residual pores in matrix is higher than other processes and processing time is relatively long. To reduce the residual porosity, the whisker-growing-assisted CVI process, which is composed of whisker growth and matrix filling steps has been developed. The whiskers grown before matrix filling may serve to divide the large natural pores between the fibers or bundles so that the matrix can be effectively filled into the finely divided pores. In this paper, the fundamentals of the CVI process for preparation of SiC f /SiC composites and some experimental results prepared by CVI and whisker-growing-assisted CVI processes are briefly introduced.