为了提高传统等温化学气相渗透(ICVI)工艺的致密化效率, 降低C/C复合材料生产成本, 本文通过减小预制体周围气体流动空间, 将传统负压ICVI工艺加以改进. 采用改进后的新型ICVI工艺, 在沉积温度1100℃、沉积压力为常压和滞留时间为0.1s的实验条件下, 以甲烷为前驱体, 氮气为稀释气体, 对纤维体积分数为28.7%的2D针刺炭毡预制体进行致密化研究, 采用偏光显微镜观察所制试样的组织结构, 测定了其三点弯曲强度, 并利用SEM观察断面形貌. 结果表明: 125h制备出密度为1.73g/cm³且密度分布均匀的C/C复合材料. 试样的组织结构为粗糙层, 弯曲强度为250.87MPa, 模量为29.29GPa, 断裂行为呈现明显假塑性.

In order to enhance densification efficiency and decrease the costs of preparation, a novel isothermal chemical vapor infiltration process for fabrication C/C composites was developed by decreasing the space of around preforms in the conventional hot wall reactor. With volume fraction of 28.7%, and infiltrated by the novel ICVI at ambient pressure and 1100℃, residence time of 0.1s, and methane as precursor, nitrogen as diluted gas, the 2D fiber felt preform was densified. The texture of the obtained sample was investigated by using a polarized light microscope and the flexural stength was determined by three-point bonding tests, after the tests, the morphology of the fracture surface was observed by using SEM. The resuts show that the bulk density of the C/C composite prepared in 125h is 1.73g/cm³, and the density distribution is uniform. Its texture is pure rough laminar. Its flexural strength is 250.87MPa. Its flexural modulux is 29.29GPa. The C/C composite exhibits a pseudo-plastic failure behavior.