Effect of HfC-SiC transition layer on the ablation resistance of SiC/HfC-SiC/HfC multi-layer coating for C/C composites

To improve the ablation resistance of SiC/HfC coating on carbon/carbon (C/C) composites in ultra-high temperature environment, HfC-SiC intermediate transition layer was prepired between SiC inner layer and HfC outer layer by supersonic atmospheric plasma spraying (SAPS). The effect of HfC-SiC transition layer on the microstructure, bonding strength and ablation resistance of the SiC/HfC-SiC/HfC multilayer coatings were investigated. Results show that the bonding strength between the outer coatings and adjacent coating increased after the introduction of the transition layer. The multilayer could effectively protect C/C composites from ablation for 60 s under oxyacetylene ablation, and the excellent ablation resistance of the multilayer coating was attributed to the transition layer inhibits the generation and propagation of cracks.