Improved CMAS corrosion resistance of high-entropy rare-earth monosilicates by multicomponent synergistic effects

Achieving superior calcium-magnesium-aluminum-silicate (CMAS) corrosion resistance of high-entropy rare-earth monosilicates (HEREMs) is of great significance to their aerospace use as environmental barrier coating materials. Here, we report the exploration of HEREMs with improved CMAS corrosion resistance through multicomponent synergistic effects. Specifically, bulk HEREMs samples with seven content ratios of rare-earth elements (HEREM- x ) were fabricated, and their CMAS corrosion resistance at 1673 K was systematically investigated. The best CMAS corrosion resistance is found to be achieved in the as-fabricated bulk HEREM-0.1 samples with the formation of the densest apatite protective layer. Further studies show that the dense apatite layer originates from the multicomponent synergistic effects, which increase the stability of the apatite structure and decrease the atomic diffusion rate of rare-earth elements in the CMAS melt.