Preparation and Structure of MoSi_2-Mo_5Si_3/SiC Multi-coating for Carbon/Carbon Composites

To prevent carbon/carbon composites from oxidation,a MoSi_2-Mo_5Si_3/SiC multi-coating was prepared by the chemical vapor reaction (CVR) technique and slurry method.The formation mechanism and structure of the multi-coating were studied by using XRD,SEM and EDS analysis, and then the anti-oxidation property of the multi-coating was investigated.The results show that the thickness of obtained coating is about 400μm,and the main phase are composed ofβ-SiC,MoSi_2 and Mo_5Si_3.After oxidation in air at 1350℃for 10h,the weight loss of the multi-coating is only 1.21%, which is obviously lower than that of single-layer SiC coating.The phases of MoSi_2 and Mo_5Si_3 formed in the MoSi_2-Mo_5Si_3/SiC multi-coating fill the cracks and holes in the monolayer SiC coating,which can improve the anti-oxidation ability of the multi-coating.So the multi-coating made by the complex technology possesses more compact structure and better anti-oxidation property.