预氧丝原位炭化无粘结剂C/C复合材料氧化动力学研究

采用恒温热重法测定了在空气中，０．１ＭＰａ，６７３Ｋ到９７３Ｋ下预氧丝（即预氧化聚丙烯腈纤维）原位炭化无粘结剂Ｃ／Ｃ复合的氧化失重率；并利用扫描电镜分析了这种复合材料氧化前后的结构，氧化动力学测定结果表明：该材料在氧化开始时，其氧化速率随时间的增长而增大，然后随时间的延长而减小，并趋向恒定，研究表明：该材料中预氧丝与基体炭界面结合处是空气中氧的扩散通道，杂质为空气中氧的吸附起到了有附活性中心的催化

A Study on the Oxidation Dynamics of Binderless C/C Composites Prepared by In-situ Carbonization of Pre-oxidized Fibres

The oxidation weight loss rate of binderless C/C composite prepared by in-situ carbonization of pre-oxidized fibres(PAN) was tested in the air,at 0.1 Mpa,from 673 K to 973 K using thermo-weight analysis method. The textures of this material before and after oxidation were analyzed under SEM. The test results show that the oxidation rate increases with the temperature going up at the beginning of oxidation,then,decreases and tends to steady state. The results show that the interface between carbon fibres and matrix carbon offers a passage for oxygen spreading,and the impurities in the material act as an active absorption center of oxygen. The dominant step for oxidation is the dissociation of absorbed oxygen.