Influence of Preparation Technology on the Structure and Phase Composition of MoSi₂-Mo₅Si₃ /SiC Multi-coating for Carbon/Carbon Composites

Xin Yang 1) , Yanhong Zou 2) , Qizhong Huang 1) , Zhean Su 1) , Mingyu Zhang 1) , Xin Chang 1) and Zhiyong Xie 1) 1) State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China 2) Materials Science and Engineering Post-doctoral Research Center, Central South University, Changsha 410083, China

摘 要：Oxidation protective MoSi 2 -Mo 5 Si 3 /SiC multi-coatings for carbon/carbon composites were prepared by chemical vapor reaction and slurry-sintering method. The influence of preparation technology on the structure and phase composition of the coating was investigated by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS） and X-ray diffraction （XRD） analyses, and then their relationship was discussed. The results indicate that the Si/Mo ratio of the slurry and sintering processing were two main factors that significantly affected the structure and phase composition of the multi-coating. Appropriate sintering process and relatively high Si/Mo ratio were essential for preparing the multi-coating with dense structure and favorable phase composition. After being sintered at 1723 K for 2 h and with the Si/Mo ratio of the slurry being 4.5 （weight ratio）, a dense structure accompanied by favorable phase composition of the coating can be obtained. When heat treated at 2373 K for 1 h, this coating became more compact and continuous. Oxidation tests （performed at 1623 and 1823 K） demonstrated that both of these two obtained multi-coatings exhibited better anti-oxidation property than single layer SiC coating.

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