The Infiltration Process and Texture Transition of 2D C/C Composites

来源 :Journal of Materials Science & Technology | 被引量 : 0次 | 上传用户:diod
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
2D needle-punched fiber felt was infiltrated by a kind of rapid isothermal chemical vapor infiltration technique. The infiltration process and texture transition of the infiltrated C/C composites were investigated. The porosity and the variations of the cumulative pore volume were determined by mercury porosimetry. The texture of matrix carbon was studied under a polarized light microscope. The results show that the relative mass gain of the sample increases directly as the infiltration time at the initial stage until 20 h, and subsequently the increasing rate of the relative mass gain decreases gradually with the prolonging of infiltration time. Three layers of pyrocarbon were formed around fibers. Low-textured pyrocarbon was obtained at the initial stage. With the densification going on, high-textured pyrocarbon was formed on the surface of low-textured pyrocarbon. Then, low-textured pyrocarbon was produced again during the final stage of densification. The texture transition is ascribed to the variation of the ratio of cumulative inner surface area to volume of pores and the gas partial pressure in pores. The infiltration process and texture transition of the infiltrated C / C composites were investigated. The porosity and the variations of the cumulative pore volume were determined by mercury porosimetry . The results of that that showed the the relative mass gain of the sample increases directly as the infiltration time at the initial stage until 20 h, and the increasing of the relative rate of the relative mass decreases With the prolonging of infiltration time. Three layers of pyrocarbon were formed around the fibers. Low-textured pyrocarbon was obtained at the initial stage. With the densification going on, high-textured pyrocarbon was formed on the surface of low-textured pyrocarbon. Then , low-textured pyrocarbon was produced again during the final stage of densification. The texture transition is ascr ibed to the variation of the ratio of cumulative inner surface area to volume of pores and the gas partial pressure in pores.
其他文献
度过愉快的寒假后,伴随着春天的脚步,一个新的学期即将开始。开学前后是辅导员们最忙碌的时间,许多工作亟待完成。结合广大辅导员的实际需求,本期我们特别推出新学期开学辅导
作文教学是语文教学的重要组成部分,作为农村中学的语文教师在确立整体意识的前提下,要抓好以下几个环节:培养爱好和积累素材,教给写作技巧,抓好立意训练。 Composition tea
清代玉器的玉材,可说完全来自新疆和田。和田所产之青玉、白玉和碧玉,每种都有洁净、粗细之分和大材、小材之别。大材之代表为故宫珍宝馆之大禹治水玉山,可谓为雕大器之首。
2008年,北京奥运会给全世界人民呈现出了一场无与伦比的盛会,既让世界进一步了解了中国,也让中国更加融入世界。随着喝彩声的落定,越来越多的奥运后思考出现了:北京奥运会究
小区电气工程施工中,强电、弱电常设计成地埋电缆进户,基础中采用了钢管的暗预埋方法,那么,钢管安装中应注意哪些事项呢?1.钢管除镀锌钢管外,均需预先除锈,刷防腐漆,现浇混
[考点点击]诗歌中的人物形象,既指诗歌塑造的人物形象(如《赤壁怀古》中的周瑜),也指诗歌的抒情主人公,或诗人自己(如《雨霖铃》中的“我”)。同时,诗歌因为讲究形象思维,作
1879年,德国人克鲁斯研究高真空放电管,实验时发现管子附近的照相底片出现了原因不明的模糊阴影。他没有去寻找产生阴影的原因,只埋怨自己不小心。过了一年,英国人古兹皮德和
题目 设抛物线C :y2 =8x ,若椭圆D的左焦点F和相应的左准线l分别与抛物线图 1 题目 1图的焦点、准线重合 ,椭圆短轴的一个端点为B ,且线段BF的中点M到定点A(m ,0 )的距离的
学生是学习的主人,老师是组织者和引导者,怎样才能让生物课堂充满生机,从而激发学生的学习热情,是每一位教师一直探索的问题。下面,笔者就如何使生物课堂充满生机的几点做法
艾哈迈达巴德(Ahmedabad),位于印度西部古吉拉特平原上,海拔55米,距阿拉伯海东北肯帕德湾96公里,是印度古吉拉特邦第一大城市。艾哈迈达巴德在古代曾因商业和手工业发展而繁盛,近代因圣雄甘地在此建立反抗英国殖民统治的不合作运动组织而成为印度近现代历史上著名的城市。20世纪末,艾哈迈达巴德因大批科技企业的迁入而逐渐成为西印度仅次于孟买的中心城市。  艾哈迈达巴德城的建立归功于古吉拉特苏丹阿默达