Improvement of ablation resistance of CVD-HfC/SiC coating on hemisphere shaped C/C composites by introducing diffusion interface

To optimize the bonding strength and ablation resistance of HfC based coating on hemisphere shaped C/C composites, a HfC-SiC diffusion interface was introduced by in-situ reaction and chemical vapor deposition. The microstructure, bonding strength and ablation resistance were characterized. After introducing HfC-SiC diffusion, the bonding strength significantly increased by 179 %. For hemisphere shaped samples, the linear and mass ablation rates decreased by 65.0 % and 53.0 %, respectively. The improvement of ablation resistance was attributed to the adhension effect of Hf-Si-O glass phase generated in outer layer and the increase of bonding strength.