Abstract Toughening a ceramic in a ceramic matrix composite (CMC) depends on an ability of the composite to tolerate an accumulation of matrix cracks. When the reinforcement phase is carbon fiber, these cracks leave the fiber susceptible to destructive oxidation by ingress of air during high temperature exposure. Generally, a graphitic carbon interface coating is applied to carbon fibers because it provides for a weak bond between fiber and matrix that is required to promote toughening. This investigation seeks to utilize a BN coating instead of a C coating in order to promote oxidation resistance. Like graphitic carbon, BN is soft and easily cleavable. Preliminary observations that C/BN/SiC CMC's using Toray T300 carbon fibers were highly brittle and of low strength lead to a requirement of heat treating the fibers prior to the CVD of BN for toughened composites to be fabricated. It is likely heat treating removed reactive functionalities from the fiber surface to yield a weakly adhered and compliant interface.

中文翻译：

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具有抗氧化氮化硼界面涂层的碳纤维增强陶瓷基复合材料

摘要 陶瓷基复合材料 (CMC) 中的陶瓷增韧取决于复合材料耐受基体裂纹积累的能力。当增强相是碳纤维时，这些裂纹会使纤维在高温暴露期间因空气进入而容易受到破坏性氧化。通常，石墨碳界面涂层应用于碳纤维，因为它在纤维和基体之间提供了促进增韧所需的弱结合。该研究试图利用 BN 涂层代替 C 涂层，以提高抗氧化性。与石墨碳一样，BN 柔软且易于切割。C/BN/SiC CMC'的初步观察 使用 Toray T300 碳纤维的 s 非常脆且强度低，因此需要在 BN 的 CVD 之前对纤维进行热处理，以制造增韧复合材料。热处理可能会从纤维表面去除反应性官能团，从而产生弱粘附和柔顺的界面。