MICROSTRUCTURAL INVESTIGATION OF LOW-DENSITY CARBON-CARBON COMPOSITES
MICROSTRUCTURAL INVESTIGATION OF LOW-DENSITY CARBON-CARBON COMPOSITES
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DOI：
10.1007/bf01162488
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发表时间：
1994-01-15
影响因子：
4.5
通讯作者：
RAWLINGS, RD
中科院分区：
文献类型：
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作者：
DAVIES, IJ;RAWLINGS, RD
采用光学显微镜、扫描电子显微镜和图像分析方法研究了低密度（0.13~0.64 Mg m(-3)）碳-碳复合材料的微观结构。所有样品最初都含有不同比例的人造丝前体碳纤维、回收纤维材料和酚醛树脂前体基质，并利用真空成型技术制造。一些复合材料通过热解碳化学气相沉积（CVD）进行致密化。所有复合材料均显示出二维平面随机微观结构，并具有明显的分层效应；在微观（有时是宏观）层面上。利用图像分析对复合材料中的分层程度进行量化，发现在不含回收材料的样品中最明显，而在含有所有纤维成分作为回收材料的样品中最不明显。发现复合材料具有非常多的孔隙，孔隙主要由相互连接的开孔组成（通常占样品体积的 65-85%）。在非 CVD 样品中，纤维材料通过薄（< 5 μm）离散的“基质键”结合在一起，结构内还存在一些大的（通常为 100 μm x 200 μm x 800 μm）纤维束。在CVD处理的材料中，纤维上的沉积涂层在整个复合材料中具有均匀的厚度，并且将先前不接触的纤维材料连接在一起。
The microstructure of low-density (0.13-0.64 Mg m(-3)) carbon-carbon composites was investigated using optical microscopy, scanning electron microscopy and image analysis. All samples initially contained varying proportions of rayon precursor carbon fibres, recycled fibrous material and phenolic resin precursor matrix, and were manufactured utilizing a vacuum moulding technique. Some of the composites were densified using the chemical vapour deposition (CVD) of pyrolytic carbon. All the composites were shown to have a two-dimensional planar random microstructure, with a distinct layering effect being seen; on the microscopic (and sometimes macroscopic) level. The degree of layering in the composites was quantified utilizing image analysis and was found to be most pronounced in samples containing no recycled material, and least pronounced in samples containing all of its fibrous constituent as recycled material. The composites were found to be very porous, the pores consisting of mainly interconnecting open pores (typically 65-85% of the sample volume). In non-CVD samples the fibrous material was held together by thin (< 5 mu m) discrete ''matrix bonds'', with a few large (typically 100 mu m x 200 mu m x 800 mu m) fibre bundles also existing within the structure. In the CVD-processed material the deposit coat on the fibres was of even thickness throughout the composite and joined together fibrous material that was not previously in contact.