航空学报 > 2015, Vol. 36 Issue (5): 1704-1712   doi: 10.7527/S1000-6893.2014.0154

纤维表面状态对C/C-SiC复合材料微观组织和相成分的影响

代吉祥, 沙建军, 王首豪, 王永昌   

  1. 大连理工大学 工业装备结构分析国家重点实验室, 大连 116024
  • 收稿日期:2014-05-13 修回日期:2014-07-08 出版日期:2015-05-15 发布日期:2014-07-21
  • 通讯作者: 沙建军Tel.: 0411-84709004 E-mail: jjsha@dlut.edu.cn E-mail:jjsha@dlut.edu.cn
  • 作者简介:代吉祥 男, 博士研究生。主要研究方向: 高温陶瓷基复合材料。 E-mail: djx725525@163.com;沙建军 男, 博士, 教授, 博士生导师。主要研究方向: 复合材料设计、制备以及性能优化。 Tel: 0411-84709004 E-mail: jjsha@dlut.edu.cn
  • 基金资助:

    国家自然科学基金(91216201); 新世纪优秀人才支持计划(NCET-11-0052); 国家教育部博士点专项基金(20130041110013)

Influence of fiber surface state on microstructure and phase composition of C/C-SiC composites

DAI Jixiang, SHA Jianjun, WANG Shouhao, WANG Yongchang   

  1. State Key Laboratory of Structure Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, China
  • Received:2014-05-13 Revised:2014-07-08 Online:2015-05-15 Published:2014-07-21
  • Supported by:

    National Natural Science Foundation of China (91216201); Program for New Century Excellent Talents in University (NCET-11-0052); Doctoral Fund of Ministry of Education of China (20130041110013)

摘要:

为了研究纤维表面状态对C/C-SiC复合材料微观组织和相成分的影响,将T300碳纤维在氮气氛围中进行不同温度的热处理后,采用液硅熔渗法制备了C/C-SiC复合材料。采用光电子能谱(XPS)对纤维表面成分进行了分析。结果表明:未处理纤维表面具有较高的氧含量,随着热处理温度的升高,纤维表面氧含量逐渐降低,导致纤维表面含氧官能团数目减少。扫描电镜(SEM)观察发现:未处理纤维增强的C/C预制体,孔隙尺寸较大且孔隙率低;而经1 500 ℃热处理纤维增强的预制体,孔隙尺寸较小但孔隙率高。随后对C/C预制体进行液硅熔渗处理,并对熔渗反应过程分析发现:由未处理纤维增强的预制体,液硅熔渗反应主要受溶解-沉淀和界面限制的扩散反应过程控制,获得的C/C-SiC复合材料中SiC基体相分布规则且含量较低,同时含有较高的残留Si;而经1 500 ℃热处理纤维增强的预制体,熔渗反应则主要受溶解-沉淀过程控制,获得的C/C-SiC复合材料中SiC基体含量多且分布较均匀,残留Si含量较少。

关键词: 纤维表面状态, C/C-SiC, 陶瓷基复合材料, 微观组织, 相成分

Abstract:

In order to investigate the influence of fiber surface state on the microstructure and phase composition of C/C-SiC composites, the surface composition of carbon fibers is modified by heat treatment, and then the fibers with different surface compositions are used to fabricate the C/C-SiC composites via liquid silicon infiltration technique. The surface composition of carbon fibers is measured by XPS (X-ray photoelectron spectroscopy). Results reveal that the oxygen content on the surface of carbon fibers decreases with increasing the treatment temperature. The low oxygen content led to small numbers of oxygen-containing functional groups, resulting in small pore size and a high porosity in C/C perform. After infiltrating the liquid silicon into C/C preform, the morphologies of C/C-SiC composites are observed by scanning electron microscopy(SEM). It is found that the microstructure and phase composition of C/C-SiC composites are quite dependent on the surface composition of carbon fibers. With decreasing the oxygen content on the carbon fiber surface, the SiC content in matrix increased, but the residual Si is reduced. Particularly, in the case of fibers with low oxygen content on the surface, there is almost no residual Si in matrix, and the composites presented a more homogeneous distribution of SiC matrix. Based on the results mentioned above, it can be seen that the microstructure and phase composition of C/C-SiC composites are controlled by the size and distribution of pores, which is closely associated with the surface state of carbon fibers. For the C/C preform with large pore size, during the liquid silicon infiltration, the formation of SiC is dominated by the solution-precipitation reaction and the interface-limited diffusion reaction mechanisms. In the case of C/C preform with small pore size, the formation of SiC is mainly controlled by solution-precipitation reaction mechanism.

Key words: fiber surface state, C/C-SiC, ceramic matrix composites, microstructure, phase composition

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