OXIDATION AND MECHANICAL-BEHAVIOR OF SIC COATED C C COMPOSITES MADE BY SI IMPREGNATION METHOD/

SiC coated C/C composites were formed by the processing route of the S i melt impregnation method, SMIM, under various temperature. The oxida tion behavior and strength of the coated C/C composites made by the SM IM were then examined to clarify advantages of this method. From the v iewpoint of oxidation resistance, the SIC coating formed by the optima l condition of the SMIM is shown to be superior to the conventional CV D methods. It is especially true when the heat treatment temperature o f the SMIM is low, i.e., just above the melting temperature of Si. Und erlying mechanisms of this superior oxidation resistance were explaine d in terms of the variation of the coating thickness and coating crack opening. By the SMIM treatment the interlaminar shear strength was al so improved remarkably but the bending strength was found to be degrad ed noticiably. It was suggested to be rather difficult to relieve the bending strength degradation by changing the SMIM treatment condition.