High Entropy Engineering: New Strategy for the Critical Property Optimizations of Rare Earth Silicates

Abstract

Environmental barrier coatings (EBCs) have been developed to improve the durability of SiCf/SiC CMC components against harsh combustion environment. Among the most promising EBC candidates, rare-earth (RE) silicates attract attentions for their low thermal expansion coefficient, excellent high temperature water vapor and CMAS corrosion resistance, and good thermal and chemical compatibility with silicon-based ceramics and composites. Herein, we reviewed the optimizations of critical properties of rare-earth silicates through strategic high entropy design to modify the current performance deficiencies of rare-earth silicates like thermal properties (coefficient of thermal expansion and thermal conductivity), CMAS corrosion resistance and high temperature phase stability. The present advancements demonstrate the merits of high entropy engineering for advanced EBCs for the improvement of crucial properties in engine applications.