Theoretical design and experimental verification of high-entropy carbide ablative resistant coating

Composition design of high-entropy carbides is a topic of great scienti fic interest for the hot-end parts in the aerospace field. A novel theoretical method through an inverse composition design route, i.e. initially ensuring the oxide scale with excellent anti-ablation stability, is proposed to improve the ablation resistance of the highentropy carbide coatings. In this work, the (Hf 0.36 Zr 0.24 Ti 0.1 Sc 0.1 Y 0.1 La 0.1 )C 1- delta (HEC) coatings were prepared by the inverse design concept and veri fied by the ablation resistance experiment. The linear ablation rate of the HEC coatings is -1.45 mu m/s, only 4.78 % of the pristine HfC coatings after the oxyacetylene ablation at 4.18 MW/m 2 . The HEC possesses higher toughness with a higher Pugh's ratio of 1.55 in comparison with HfC (1.30). The in-situ formed dense (Hf 0.36 Zr 0.24 Ti 0.1 Sc 0.1 Y 0.1 La 0.1 )O 2- delta oxide scale during ablation bene fits to improve the anti-ablation performance attributed to its high structural adaptability with a lattice constant change not exceeding 0.19 % at 2000 -2300 degrees C. The current investigation demonstrates the effectiveness of the inverse theoretical design, providing a novel optimization approach for ablation protection of high-entropy carbide coatings.