Ablation performance of C/HfC-SiC composites with in-situ HfSi2/HfC/SiC multi-phase coatings under 3000℃ oxyacetylene torch

A HfSi 2 /HfC/SiC multi-phase coating with reticular HfSi 2 as a skeleton was in-situ formed on the surface of C/HfC-SiC composite after RMI process. After ablation for 120 s, the linear and mass ablation rate of the prepared composites was − 2.33 ± 0.14 µm/s and − 0.06 ± 0.03 mg/s·cm 2 , respectively. In the central region, there were voids inside coating and a gap was between the coating and substrate, while in the transitional region a dense HfC 1−x O x -HfO 2 -SiC mixed layer effectively protected substrate from ablation. In the brim region, only the coating near-surface was ablated. The results proved infinite potential of C/HfC-SiC composites with in-situ coating in ablation resistance. • A HfSi 2 /HfC/SiC multi-phase coating was in-situ formed on the surface of the C/HfC-SiC composite prepared by RMI. • C/HfC-SiC composite with an in-situ coating showed excellent ablation resistance under 3000℃ oxyacetylene torch for 120s. • After ablation three typical ablation regions with different structures were observed on the surface. • The ablation mechanism of typical ablation regions was systematically studied.