原位生长的气相生长碳纤维增强C/C复合材料的制备及其弯曲性能

以丙烯为碳源, FeCl₃·6H₂O为催化剂, 采用化学气相沉积法(CVD)在碳毡和不同密度的C/C复合材料上原位气相生长碳纤维(VGCFs) , 并以含原位生长VGCFs的碳毡和不同密度的C/C复合材料为基体制备VGCFs-C/C复合材料。研究了反应压力、基体密度对VGCFs生长情况的影响, 借助扫描电镜(SEM)、光学显微镜观察原位生长VGCFs的形貌及基体原位生长VGCFs后热解炭形貌的变化, 并对比研究了C/C复合材料和VGCFs-C/C复合材料的弯曲性能。研究结果表明, 反应压力为3700 Pa, 基体密度低的情况更有利于VGCFs的生长; 原位生长的VGCFs改变了纤维表面热解炭的沉积形貌, 使得热解炭和碳纤维的结合面之间形成具有铆钉作用的球状结构, 增强了界面结合力, 从而提高了原位生长的高VGCFs含量样品的弯曲强度。

Preparation and Flexural Property of In-situ Vapor Grown Carbon Fibers Reinforced C/C Composites

The in-situ vapor grown carbon fibers (VGCFs) were synthesized by chemical vapor deposition (CVD) on carbon felt and C/C composites of different densities, using propylene as carbon resources and FeCl₃·6H₂O as catalyst. And VGCFs-C/C composites were prepared on carbon felt and C/C composites of different densities with in-situ VGCFs. The effects of pressure in the reactor and density of the substrate on growth of VGCFs were investigated, and the morphology of in-situ VGCFs and the change of morphology of pyrolytic carbon on the substrate with in-situ VGCFs were observed by scanning electron microscope (SEM) and optical microscope. In addition, the flexural properties of C/C composites and VGCFs-C/C composites were investigated. Results show that low density of substrate is beneficial to the in-situ growth of VGCFs when the pressure in the reactor is 3700 Pa. In-situ VGCFs change the morphology of pyrolytic carbon, and induce the formation of the spherical structure, which can enhance the interface bonding force like nails doing. Therefore, the flexural strength of sample with high content of VGCFs is improved.