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 ＢＮ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．
High performance SiC(f)/SiC composites were fabricated by chemical vapor infiltration (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 processing, 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.
参考文献
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