Influence of Fiber Pre-coating on Mechanical Properties and Interfacial Structures of SiC(f)/SiC Composites
纤维表面涂层对SiC(f)/SiC复相陶瓷力学性能和界面结构的影响

High performance SiC(f)/SiC composites were fabricated by chemical vapor infiltra- tion (CVI) processing. The effects of pre-coating of SiC fiber on the mechanical properties and microstructures of SiC(f)/SiC composites were investigated. It was found that the introduction of C or BN pre-coating on SiC fiber surface could promote the pull-out of fiber and interfacial debonding in the course of fracture markedly coupled by great increases of fracture toughness and work of fracture. SEM micrographs indicated that strong interfacial bonding between fiber and matrix was changed, suggesting that the brittle fracture mode of SiC(f)/SiC composite without any pre-coating was improved. HREM observation showed that in the initial period of CVI pro- cessing, graphite interphase with obvious layered configuration with better crystallization degree was first deposited on the surface of fiber, whereas the C pre-coating on SiC fiber was amorphous.