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以2D针刺炭毡为预制体,天然气为炭源前驱体,无稀释气体,绝对压力为10kPa,沉积温度为1100℃的工艺条件下,通过新型等温化学气相沉积工艺(ICVI),控制气体滞留时间分别为0.01,0.02,0.03s。研究在此超短气体滞留时间下C/C复合材料的致密化过程及密度分布,并采用偏光显微镜(PLM),扫描电子显微镜(SEM)观察其微观组织结构形貌。结果表明:在0.01s的气体滞留时间下,150h的渗透时间内可以制备出表观密度达到1.75g/cm3以上,密度呈现内高外低特点的C/C复合材料,其组织结构为中织构(MT)和高织构(HT)的双层织构,MT只在纤维表面存在且厚度小于2μm,其他均为HT组织。
A new isothermal chemical vapor deposition (ICVI) technique was used to control the gas retention under the conditions of 2D needle punched carbon felt as preform and natural gas as precursor of carbon source, without dilution gas, absolute pressure of 10kPa and deposition temperature of 1100 ℃. Time was 0.01,0.02,0.03 s. The densification process and density distribution of C / C composites under ultra-short gas residence time were investigated. The microstructure and morphology of the C / C composites were observed by polarized light microscopy (PLM) and scanning electron microscopy (SEM). The results show that the C / C composites with apparent density above 1.75g / cm3 and high and low internal density can be prepared during infiltration time of 150h under gas residence time of 0.01s. (MT) and high-textured (HT) double-layer textures. MT only exists on the surface of the fiber and its thickness is less than 2μm. The others are all HT tissues.