Oxidation and erosion resistant property of SiC/Si-Mo-Cr/MoSi₂ multi-layer coated C/C composites

To improve the oxidation and erosion resistance of C/C composites, a multi-layer SiC/Si-Mo-Cr/MoSi₂ coating was prepared on them by a combination technique of pack cementation and a super supersonic plasma spraying technique. X-ray diffraction and scanning electron microscopy were used to analyze the phase and microstructure of the coatings. After a static oxidation test at 1773 K in air for 200 h, compared with the SiC/Si-Mo-Cr coated samples, the mass loss of the SiC/Si-Mo-Cr/MoSi₂ coated samples decreased by 56.1%. After adding a MoSi₂ layer on the SiC/Si-Mo-Cr coating by the super supersonic plasma spraying, the corrosion protection time in a wind tunnel at 1873 K could be prolonged from 93 h to 124 h. The deposited outer MoSi₂ layer could act as oxygen barrier layer and seal the initial penetrating cracks in the SiC/Si-Mo-Cr coating, resulting in the improvement of the oxidation and erosion resistance of the coated samples.