ポリカルボシランの含浸と熱分解による炭素繊維強化炭化ケイ素複合材料の作製と破壊挙動

概要

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Three types of carbon fibers, PAN-based HSCF, pitch-based HMCF with low graphitization degree, and pitch-based CF70 with high graphitization degree, were used to prepare unidirectional carbon fiber reinforced SiC composites(CF/SiC) by multiple impregnation of polycarbosilane and subsequent pyrolysis at 1200℃ for 5-9 times. The experimental results showed that pyrolytic product of polycarbosilane at 1200℃ in N_2 consisted of β-SiC phase in a nearly amorphous state and impurity oxygen. The impregnation behavior of polycarbosilane for CF70/SiC was different from those of HSCF/SiC and HMCF/SiC. CF70/SiC showed a flexural strength of 700 MPa, which was markedly higher than those of HSCF/SiC and HMCF/SiC. Moreover, CF70/SiC exhibited non-catastrophic fracture behavior, whereas HSCF/SiC and HMCF/SiC showed brittle fracture behavior. Scanning electron microscope(SEM) and transmission electron microscope(TEM) observation of these composites clarified that HSCF/SiC and HMCF/SiC had a strong fiber/matrix interface bonding, whereas CF70/SiC had a weak interface bonding. It was concluded that highly graphitized CF70 was the most suitable reinforcement for the CF/SiC composite.
社団法人日本セラミックス協会の論文
1998-12-01