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

报道了化学气相浸渍（CVI）工艺制备的SiC（f）/SiC复相陶瓷中纤维表面涂层对复合材料力学性能和显微结构的影响。SEM观察表明：C或B N表面涂层改变了SiC（f）/SiC复相陶瓷中纤维与基体间的强界面结合，使断裂过程中的界面解离和纤维拔出大大增加，与此同时材料的断裂韧性和断裂功明显提高。说明C或BN纤维表面涂层能够大大地改善SiC（f）/SiC复相陶瓷的脆性断裂行为模式。高分辨电镜的观察证实在CVI过程初期，纤维表面首先发生石墨界面相的沉积，该界面相具有明显的层状晶格条纹，而纤维表面C涂层为无定型态。

Influence of Fiber Pre-coating on Mechanical Properties and Interfacial Structures of SiC(f)/SiC Composites

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.