中文摘要：

分别以天然气和丙烯为前驱体制备了C／C复合材料。考察了密度和密度分布，借助偏光显微镜观察了沉积炭的显微结构，研究表明，天然气制备的C／C复合材料的密度大于丙烯制备的C／C复合材料的密度；在前60h以天然气为前驱体时C／C复合材料的致密化速率比以丙烯为前驱体时低，60h后致密化速率发生逆转；以天然气为前驱体所得C／C复合材料的密度梯度小，结构为单一的粗糙层；而以丙烯为前驱体所得C／C复合材料的密度梯度大，结构为光滑层。

英文摘要：

C/C composites are prepared by using natural gas and propylene as precursors. The density and its distribution are studied, and the microstructures of pyrocarbons are observed by polarized light microscopy. The results show that： the density of composites using natural gas as precursor is higher than that using propylene. The densification rate of C/C composites using natural gas as precursors is lower than that using propylene as precursors in the first 60h, while after 60h the trend is reversed. The density of C/C composites prepared by natural gas tends to distribute uniformly, and the texture belongs to rough laminar; the density of C/C composites prepared by propylene tends to distribute unevenly, and the texture belongs to smooth laminar.