LAUSR

ABSTRACT In this research, the high-duration ablation resistance of SiC-gradient coating was investigated. SiC coating was prepared on graphite by reactive melt infiltration method at 1873 K under the argon atmosphere. Formation of the SiC layer with gradient distribution of Si and C elements was confirmed by X-ray diffraction patterns and scanning electron microscope micrographs. The results of the ablation test showed that SiC-graded coating with a proper adhesion could protect the graphite substrate up to 2073 K. The mass ablation rate for the SiC-graded coating after the 60 and 360 s ablation test under supersonic flame were −0.346 × 10−3 g/cm2 s and −0.022 × 10−3 g/cm2 s, respectively. The results indicated that the ablation mechanism of the SiC coating under supersonic flame is the SiO2 scouring from the central ablation region to the outer ablation region in the layer by layer form.