Transmission electron microscopy study of the microstructure of carbon/carbon composites reinforced with in situ grown carbon nanofibers

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• 作者：Yequn Liu^a ; ^c ; LianLong He^a ; ^{llhe@imr.ac.cn} ; XueFeng Lu^b ; Peng Xiao^b
• 刊名：Carbon
• 出版年：2012
• 期刊代码：10_00086223
• 类别：ms
• 出版时间：June, 2012
• 卷：50
• 期：7
• 页码：2424-2430
• 文件大小：1010 K

摘要

Introduction of carbon nanofibers (CNFs) into carbon/carbon (C/C) composites is an effective method to improve the mechanical properties of C/C composites. In situ grown CNFs reinforced C/C composites as well as conventional C/C composites without CNFs were fabricated by chemical vapor infiltration. Transmission electron microscopy investigations indicate that the entangled CNFs (30-120 nm) formed interlocking networks on the surface of carbon fibers (CFs). Moreover, a thin high-textured (HT) pyrocarbon (PyC) layer (鈭?0 nm) was deposited on the surface of CFs during the growth of CNFs. We find the microstructure of C/C composites depends strongly on the local distribution density (LDD) of CNFs. In regions of low CNF LDD, a triple-layer structure was formed. The inner layer (attached to CF) is HT PyC (鈭?0 nm), the middle layer (150-200 nm) is composed of HT PyC coated CNFs (HT/CNFs) and medium-textured PyC, and the outmost layer (several microns) is composed of HT/CNFs and micropores. In regions of high CNF LDD, a double-layer structure was formed. The inner layer is HT PyC (鈭?0 nm), and the outer layer is composed of HT/CNFs, isotropic PyC and nanopores. However, only medium-textured PyC and micropores were found in the matrix of the conventional C/C composites.