Fabrication and characterization of SiC f/SiC composite by CVI using the whiskering process

Abstract

The chemical vapor infiltration (CVI) process is an effective method for fabricating SiC fiber-reinforced SiC matrix composites but it is slow with an inherent drawback of substantial residual porosity. To obtain the dense SiC f/SiC composite by the CVI process, in situ whisker growing and matrix filling (called whiskering process) was applied. The process was designed to reduce the canning effect during the CVI process and may serve to divide the large natural pores between fibers or bundles by the grown whisker and then fill the matrix inside the modified pore structure. This process was performed using MTS (CH 3SiCl 3) as a source gas and H 2 or N 2 as a diluent and the amounts of the whiskers into the matrix phases were changed by controlling the whiskering cycles. The infiltration effects, that is, increasing of the density of the SiC f/SiC composite were investigated. And the improved SiC f/SiC composites were fabricated using this process.