Fabrication and high-temperature flexural strength of a sintered SiC fiber reinforced SiC composite

Abstract

A sintered SiC polycrystalline fiber, which has been developed by UBE Industries, Ltd., possesses high modulus, excellent thermal stability and oxidation resistance. A SiC matrix composite reinforced by the sintered SiC fiber was fabricated by polymer impregnation and pyrolysis (PIP) method. The composite consisted of 26 vol% 3-D sintered SiC fabric and polymer-derived SiC matrix. Carbon coating was applied by chemical vapor deposition on the 3-D sintered SiC fabric prior to the matrix densification. Three point flexural tests of the sintered SiC fiber reinforced SiC composite up to 1400°C in Ar were carried out, and the results were compared with a SiC matrix composite-reinforced by an amorphous Si-Zr-C-O fiber. The flexural strength of the sintered SiC fiber reinforced Sic composite at 1400°C retained 84% of the strength at room temperature, while that of the amorphous Si-Zr-C-O fiber reinforced SiC composite retained only 56%. In addition, the sintered SiC fiber reinforced SiC composite showed higher stiffness than that of the amorphous Si-Zr-C-O fiber reinforced SiC composite. The higher retention ratio of the strength at 1400°C and higher stifness of the sintered SiC fiber reinforced SiC composite were attributed to excellent heat resistance and high tensile modulus of the sintered SiC fiber.