中文摘要：

研究了反应气体浓度对微正压等温化学气相沉积制备的C／C复合材料密度和显微结构的影响，结果表明：在微正压和900℃的沉积条件下，用丙烯作为碳源、针刺毡作为预制体，氮气与丙烯的气体流量比为25：1，经过105h沉积后，C／C复合材料的密度达到1．52g／cm^3；通过偏光显微镜观察分析发现试样外部除了围绕在炭纤维周围的光滑层外，还沉积了大量的再生结构热解炭，试样内部主要以光滑层结构为主．图7，参12．

英文摘要：

The influence of concentration of reaction gases on the density and microstructure of C/C composites prepared by micro-positive ICVI was studied. Results indicate that using the needle-punched carbon felt as porous preforms, C3H6 as hydrocarbon gas, and under the condition that the current ratio of N2 to C3H6 was 25 ： 1, the temperature was 900 ℃ and the furnace pressure was micro-positive , C/C composite with the density of 1.52 g/cm^3 was reached after 105 hours. Pyrocarbon microstructures were investigated with polarized optical microscope （PLM）. The smooth laminar was obtained in the circumference of carbon fibers and large amounts of regenerative pyrocarbon in the circumference of smooth laminar in the exterior of the sample, the smooth laminar was mainly found in the interior of the sample. 7figs., 12refs.