Influence of Cr content on the microstructure and anti-oxidation property of MoSi₂-CrSi₂-Si multi-composition coating for SiC coated carbon/carbon composites

A MoSi₂-CrSi₂-Si multi-composition coating was prepared on the surface of SiC coated carbon/carbon (C/C) composites by pack cementation in argon. The crystalline structure of the multi-composition coating was measured by X-ray diffraction. The morphology and the element distribution were analyzed by scanning electron microscopy and energy dispersive spectroscopy, respectively. The influence of Cr content in pack powder on the microstructure and oxidation resistance of the multi-layer coating were investigated. The results indicated that with the increase of Cr content in pack powder, the compound including MoSi₂ and CrSi₂-Si content increased. While frequency of crack in the coating obviously increased with the increase of compound content. The multi-layer coating prepared with Cr content of 10 wt.% exhibited excellent oxidation protection for C/C composites at 1600°C in air for 400 h.