Hafnium carbide protective layer coatings on carbon/carbon composites deposited with a vacuum plasma spray coating method

A pure hafnium-carbide (HfC) coating layer was deposited onto carbon/carbon (C.C) composites using a vacuum plasma spray system (VPS). By introducing a SiC buffer layer, we successfully integrated C.C composites with a 110-μm-thick protective coating layer of HfC. Compared to the conventional chemical vapor deposition process, the HfC coating process by VPS showed increments in the growth rate, thickness, and hardness. The growth behavior and morphology of HfC coatings were investigated by FE-SEM, EDX, and XRD. In addition, the thermal ablation test results showed that the HfC coating layer perfectly protected the C.C layer from thermal ablation and oxidation. Consequently, we expect that this ultra-high temperature ceramic coating method, and the subsequent microstructure that it creates, can be widely applied to improve the thermal shock and oxidation resistance of materials under ultra-high temperature environments.