High-throughput composition screening of high-entropy rare-earth monosilicates for superior CMAS corrosion resistance up to 1873 K

Abstract

Superior calcium-magnesium-aluminum-silicate (CMAS) corrosion resistance is the key to the applications of high-entropy rare-earth monosilicates (HEREMs) as environmental barrier coatings (EBCs) for next-generation gas turbine engines. Here, we report a high-throughput composition screening strategy to achieve superior CMAS corrosion resistance in HEREMs for the first time. Specifically, we first fabricate ten kinds of (Ho0.25Yb0.25Lu0.25X0.25)2SiO5 (X = Sc, Tm, Er, Y, Dy, Gd, Eu, Sm, Nd, and La) HEREM samples using a high-throughput pressure-less sintering technique, and subsequently screen their CMAS corrosion resistance at 1673 K via a high-throughput testing apparatus. Among all the as-fabricated samples, the HEREM-Er samples are found to have the best CMAS corrosion resistance, even up to 1873 K, which outperforms the EBC materials that have been reported. Such superior CMAS corrosion resistance of the HEREM-Er samples is primarily attributed to the formation of a dense apatite barrier layer, which results from its decreased melting point, as confirmed by first-principles calculations and molecular dynamic simulations. Our work provides a guide for designing exceptional anti-CMAS corrosion high-entropy rare-earth silicates.