Interface Formation of Unidirectional SiCf/SiC Composites by Electrophoretic Deposition Method

C-and BN-interphases on SiC fibers for unidirectional SiCf/SiC composites were formed by EPD process, and their microstructure and mechanical properties were investigated. Whereas the C-SiCf/SiC composites showed a pseudo-ductile fracture behavior with large amount of fiber pullout, the BN-SiCf/SiC composites fractured in a brittle manner without fiber pullout in spite of sufficient thickness of BN interphase. It is inferred from the results of EDS that sintering additives would react with h-BN-interphase, and the interphase did not act effectively for toughening the SiCf/SiC composites.