Preparation of SiC/C composite sheet from polycarbosilane/carbon-based resin mixture

SiC/C composites were prepared from a mixture of polycarbosilane and phenolic resin with weight ratio of 2/1 and 1/1 using PVB as a binder. The two types of green bodies which were formed by mould pressing method were treated in the temperature range from 1,000 degrees C to 1,500 degrees C under nitrogen. X-ray diffraction patterns, density, flexural strength and fracture surfaces of the composite were examined. The flexural strength of the composites at room temperature increased with heat-treatment temperature and showed a maximum value of 175 MPa at 1,300 degrees C. When the composite was heat treated at 1,400 degrees C, the flexural strength decreased rapidly due to the crystallization of SiC. The SiC/C composites showed good oxidation resistance up to 830 degrees C. The effective mixing ratio of PCS/phenolic resin to obtain improved mechanical property was 2/1.