The CMAS corrosion behavior of high-entropy (Y0.2Dy0.2Er0.2Tm0.2Yb0.2)4Hf3O12 hafnate material prepared by ultrafast high-temperature sintering (UHS)

High-temperature molten calcium-magnesium-alumina-silicate (CMAS) corrosion has become a fatal factor for the failure of aero-engine thermal barrier coatings. In this study, a promising entropy-stabilized (Y0.2Dy0.2Er0.2Tm0.2Yb0.2)4Hf3O12 (5YH) hafnate was prepared by the emerging ultrafast high-temperature sin -tering (UHS), and its corrosion and wetting behavior of molten CMAS were investigated. For the corrosion mechanism, the precipitation of the high-entropy apatite phase promotes the formation of the HfO2 phase, and it can improve the density and stability of the slow-growing reaction layer, hindering the further penetration of molten CMAS. At 1300 celcius, a reaction layer with a three-layered morphology is generated, resulting from the decreased viscosity of the molten CMAS. Moreover, computational analysis shows that molten CMAS on the 5YH surface has a larger contact angle (17 degrees) than traditional YSZ (13 degrees), and the spreading area is about 90 % of traditional YSZ, which benefits for its good CMAS corrosion resistance.

Automated summary

In this study, a promising entropy-stabilized (Y0.2Dy0.2Er0.2Tm0.2Yb0.2)4Hf3O12 (5YH) hafnate prepared by ultrafast high-temperature sin-tering was investigated for its corrosion and wetting behavior in molten CMAS environment. The results showed that the precipitation of high-entropy apatite phase promoted the formation of HfO2 phase, improving the density and stability of the reaction layer, thus hindering the penetration of molten CMAS.