高熵化设计:稀土硅酸盐材料关键性能优化新策略

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

环境障涂层是先进航空发动机高温结构部件用碳化硅纤维增强碳化硅(SiCf/SiC)陶瓷基复合材料的关键防护。稀土硅酸盐具有低热膨胀系数、优良的抗水氧/CMAS腐蚀性能以及与硅基陶瓷良好的化学相容性,是目前国际公认的优选环境障涂层体系。常规含单一稀土元素的稀土硅酸盐环境障涂层材料,存在热应力失配、高温相转变和耐腐蚀性能差等问题,尚无法完全满足极端燃气环境中的长寿命服役要求。本综述介绍了为解决稀土硅酸盐环境障涂层的关键性能局限,利用高熵化合物设计方法,针对稀土硅酸盐热学性能(热膨胀系数和热导率)调控、耐CMAS腐蚀性能提升和相结构稳定性优化方面获得的新进展。这些研究进展为稀土硅酸盐材料的创新设计提供了新思路,为其作为下一代环境障涂层的性能突破提供了支撑。

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.