科研之友
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摘要
Carbon fiber-reinforced SiC matrix (C-f/SiC) composites were fabricated using a chemical vapor infiltration + polymer infiltration and pyrolysis (CVI+ PIP) hybrid process. In an effort to improve the yield of SiC pyrolyzed during PIP, we conducted pyrolysis under high pressure using polycarbosilane as a precursor. We investigated the effects of the high-pressure pyrolysis of the polycarbosilane infiltrate on the efficiency of the PIP process and the physical characteristics of the fabricated C-f/SiC composites. The CVI + PIP hybrid process under high-pressure pyrolysis reduced the processing time by a factor of ten, minimized the oxygen content (< 10 at %) and improved the crystallinity of the nano beta-SiC crystal. These results are due to the pressure in the polycarbosilane pyrolysis, which resulted in a high polycondensation. The ceramic yield of polycarbosilane infiltrated into C-f-preform was increased and the inter-facial bonding between the matrix and fibers was improved. Consequently, the C-f/SiC composites fabricated by the CVI + PIP hybrid process under high-pressure pyrolysis exhibited a high density of 2.15 g/cm 3.
- 出版日期2014-7
