不同预制体结构C/C复合材料的CVI致密化行为  

Densification Behavior of C/C Composites with Different Preforms by Chemical Vapor Infiltration

作　　者：李艳[1] 崔红[1,2] 赵新来[2] 李世山[2] 嵇阿琳[2] 

机构地区：[1]西北工业大学材料学院,西安710072 [2]西安航天复合材料研究所,西安710025

出　　处：《硅酸盐学报》2017年第7期1031-1036,共6页Journal of The Chinese Ceramic Society

基　　金：国防基础科研项目(C0320110006)

摘　　要：采用化学气相渗透(CVI)工艺分别对整体毡和针刺毡厚壁预制体进行了500 h的致密化,研究了2种预制体的致密化效率、微观结构及密度分布情况。结果表明:预制体结构对C/C复合材料的致密化行为影响较大。致密化前期,整体毡预制体表现出较高的致密化效率,后期效率下降较快,热解炭包裹在纤维之间,材料内部密度分布不均,呈现两边高中间低的现象。针刺预制体在CVI前期致密化效率较低,热解炭主要包裹在纤维束外,致密化后期致密化效率下降较慢,致密后材料内部密度分布均匀。与整体毡预制体相比,针刺预制体的孔隙平直,分布均匀,更有利于碳源气体的深入渗透以获得均匀的密度分布。Two kinds of thick-wall C/C composites were prepared via chemical vapor infiltration （CVI） using integral felt and needled felt as reinforced preforms. The densification efficiency, microstructure and density distribution were investigated. The results show that the structure of preform has a great influence on the densification behavior. For the integral felt preform, its densification efficiency is great during the initial infiltration of CVI, but it decreases rapidly afterwards. The thicker pyrocarbon layers are wrapped around fibers, showing a radially heterogeneous density distribution. For needled preform, its densification efficiency is lower than that of the integral felt preform during the initial infiltration of CVI, but decreases slowly at the subsequent stage of CVI. Pyrocarbon mainly exists outside the bundle of fibers, exhibiting the uniform radial density distribution. Compared to the integral felt preform, the pores of needled preform are flat, straight and uniform distribution, which are more suitable for the penetration of gas into the preform and favors to obtain the uniform density distribution.

关 键 词：针刺预制体 化学气相渗透 致密化效率 密度分布 

分 类 号：TB332[一般工业技术—材料科学与工程]