中文摘要：

分别采用石油液化气和丙烯作为碳源、氮气作为载气、针刺毡作为多孔预制体，在微正压ICVI沉积炉中制备炭／炭复合材料，沉积温度为820～970℃，每个样品均沉积120h。研究不同的碳源对材料增密、密度均匀性和显微结构的影响，采用偏光显微镜和扫描电镜观察热解炭的显微结构和沉积表面形貌，采用排水法测量材料的密度。研究结果表明，在不同碳源条件下，材料的密度都随沉积温度的升高先增加后减小，热解炭均为中等织构，但是，其微观组织形貌存有差别；以石油液化气作为碳源，在940℃沉积密度达到1．53g／cm^3，样品内外存在0．022g／cm^3密度梯度，沉积表面形貌粗糙、有球状的凸起；丙烯作为碳源，在880℃沉积密度达到1．51g／cm^3，样品内外存在0．036g／cm^3密度梯度，沉积表面光滑。

英文摘要：

Using liquefied petroleum gas （LPG） and C3H6 as carbon sources, N2 as carrier gas, needle-punched carbon felt as porous preforms, C/C composites were fabricated at 820-970 ℃deposited for 120 h under micro-positive pressure by isothermal chemical vapor infiltration （ICVI）. The influences of different carbon sources on the densification, density uniformity and microstructure were investigated. The textures and surface morphologies of pyrocarbons were observed by polarized light microscopy （PLM） and scanning electron microscopy （SEM） separately, and the bulk density of these C/C composites were measured by water displacement method. The results show that the bulk densities of the samples using different carbon sources increase firstly, and then decrease with the increase of deposition temperature. The textures of pyrocarbon using different carbon sources are medium-textured, but their microstructures are difference. The average density of sample using LPG as carbon source is 1.53 g/cm^3 at 940 ℃, and there exist 0.022 g/cm^3 density grads in the inside and outside of sample, and the morphology of deposition surface is rough and has sphericity protruding. The average density of sample using C3H6 as carbon source is 1.51 g/cm^3 at 880 ~C, and the inside and outside of sample possess 0.036 g/cm^3 density grads, and the morphology of deposition surface is smooth.