Enhanced ablation resistance of ZrC–ZrO2 nanocomposite ceramic coating on TiAlNb medium-entropy alloy prepared by a novel strategy.

A novel one-step liquid plasma-assisted particle deposition and sintering (LPDS) method is used to prepare a ZrC–ZrO 2 nanocomposite ceramic coating on a TiAlNb medium-entropy alloy to enhance its ablation resistance. For comparison, a conventional plasma electrolytic oxidation (PEO) ceramic coating is fabricated on a substrate without ZrC particles. Results show that numerous ZrC particles are introduced into the coating, accompanied by partial oxidation to ZrO 2 during the LPDS. The thickness of the nanocomposite coating increases significantly by approximately 11.4 times compared with that of the PEO coating. At 1000 °C, the ablation thickening of the ZrC–ZrO 2 nanocomposite coating is approximately 1/4 of that of the substrate after ablation in air. Moreover, 17.88% and 2.83% of the substrate surface and PEO coating are peeled, respectively, whereas no peeling occurred in the ZrC–ZrO 2 nanocomposite coating. This can be attributed to the high melting point and exceptional toughness of ZrO 2 , which allow it to absorb the stress caused by thermal shocks and inhibit crack formation. A thick nanocomposite coating is crucial for protecting the substrate by preventing oxygen from permeating the coating and oxidizing the substrate. Additionally, the glass phase of SiO 2 densifies the pores and cracks in the coating, thereby significantly inhibiting the inward diffusion of oxygen and preventing ablation. Therefore, LPDS is a novel strategy for designing and fabricating multifunctional coatings to enhance the thermal protection of alloy substrates via the incorporation of various functional particles. [ABSTRACT FROM AUTHOR]