中文摘要：

在传统CVI工艺的基础上,提出了一种新的炭/炭复合材料沉积致密化技术—微波热解CVI工艺。该工艺采用微波炉加热炭毡预制体,预制体自身发热,并通过控制微波场强分布和热传导过程产生温度梯度,加上微波对极性分子的极化作用和对热解反应和表面沉积反应的催化作用,使预制体从中心至表面逐层快速致密。通过考察炭毡预制体经微波加热后的温度场分布和沉积样品的体积密度变化和径向密度分布,观察材料的微观结构,分析了预制体的致密化过程。结果表明：微波热解CVI工艺在1075℃～1150℃的沉积温度下,以甲烷为碳源前驱体,经90h的热解沉积,成功制备出体积密度为1.70g/cm^3的炭/炭复合材料,平均致密化速率达到0.0189g/（cm^3·h）;避免了表面结壳现象,热解炭沿着纤维表面层状生长;采用该工艺制备了结构均匀、主要为中等织构的热解炭。

英文摘要：

Microwave assisted chemical vapor infiltration （CVI） was carried out to prepare carbon/carbon composites in a home-made microwave furnace in the temperature range of 1075-1 150℃, using carbon fiber felt as the substrate and and methane as the pyrolytic carbon precursor. The felts were heated by absorbing microwave energy. Because the selective heating of the carbon fiber surface by polarization of polar groups on the carbon fiber surface and the catalytic effect of homogeneous gas-phase reactions by microwaves, the preform was densified from center to surface to a bulk density 1.70 g/cm^3 after CVI for 90 h. The densification rate was increased to 0. G189g/（cm^3·h）. The pyrolytic carbon has a smooth laminar structure along carbon fiber surface. The radial density distribution of carbon investigated by optical microscopy indicates that plugging of the surface pores is avoided in the carbon fiber felts and the microstructure of the materials is uniform, having a medium texture.