CVD热解炭的结构、生长特征及可石墨化性

Structure, Growth Feature and Graphitizability of Chemical VaporDeposited Pyrolitic Carbons

采用TEM表征结构、喇曼光谱表征石墨化度,研究了C/C复合材料中典型粗糙层(RL)和光滑层(SL)结构热解炭生长特征及其与可石墨化性之间的对应关系.结果表明,RL为层状结构,片层呈平直形状,有明显的锥状生长特征,同一锥面中石墨微晶c轴的取向基本相同,相邻锥面中的相差一个小角度,SL没有明显的生长特征;RL比SL结构热解炭容易石墨化,经2400℃石墨化处理后,两者(002)衍射弧宽度分别为39°和66°,对应的石墨化度分别为87.6％和25.6％.提出了一种RL结构热解炭锥状生长结构模型.

The structure, growth feature and graphitizability of typical rough laminar (RL) and smooth laminar (SL) pyrolitic carbons in carbon/carbon composites were studied by using transmission electron microscopy and laser Raman spectroscopy. The results show that RL pyrolitic carbon is characterized by a plate-like structure and featured by growth cones. The c axis of every crystallite in the same cone is parallel each other, and there is a small angle between those in the adjacent cones. Whereas no obvious growth feature can be observed in SL pyrolitc carbon. RL pyrolitic carbon is more graphitizable than SL. Heat treated at 2400degreesC, the angular width of the (002) diffraction arc of them are 39degrees and 66degrees respectively, and the graphitization degree 87.6% and 25.6%. A growth model was proposed to explain the growth feature of RL pyrolitic carbon.