In-situ preparation and ablative resistance of multicomponent refractory carbide ceramic gradient coatings

In this work, the gradient multicomponent carbide ceramic coatings were prepared in-situ on graphite matrix using the molten salt method, and their high temperature ablation resistance was investigated. Our results demonstrate the successful preparation of (HfTi)C, (HfTiZr)C, and (HfTiZr)C–TaC ceramic coatings with a gradient distribution on the graphite matrix by altering the types of raw materials. Thermodynamic calculations and analyses indicate that the smaller the Gibbs free energy gap between different carbides, the easier the solid solution multicomponent ceramic coating is formed. After 200 s of oxy-acetylene torch ablation, it was observed that the (HfTi)C, (HfTiZr)C, and (HfTiZr)C–TaC coatings effectively protected the graphite matrix with mass ablation rates of 6.47 mg s −1 , 0.61 mg s −1 , and 0.51 mg s −1 , respectively. The low mass loss of (HfTiZr)C and (HfTiZr)C–TaC coatings can be attributed to the synergistic protective effect of different oxides formed by oxidation of different elements.