Synthesis and Property of High-Entropy Rare Earth Hafnate as Thermal/Environmental Barrier Coating Material
HU Wanpeng1,2, ZHANG Guangheng1,2, ZHANG Jie1, WANG Jingyang1
1. Shenyang National Laboratory for Materials Science, Institute of Metal Research,
Chinese Academy of Sciences, Shenyang 110016, China;
2. University of Science and Technology of China, Shenyang 110016, China)
Thermal/environmental barrier coating with optimized performance is critical for the application in advanced aero-engines. In this work, high-entropy rare-earth hafnates, （La0.2Gd0.2Ho0.2Er0.2Tm0.2）4Hf3O12 and（Yb0.2Lu0.2Ho0.2Er0.2Tm0.2）4Hf3O12, were prepared by a two-step sintering method. Mechanical properties, thermal properties and CMAS corrosion behavior of two materials were systematically investigated. （Yb0.2Lu0.2Ho0.2Er0.2Tm0.2）4Hf3O12exhibits higher hardness and fracture toughness than that of (La0.2Gd0.2Ho0.2Er0.2Tm0.2)4Hf3O12. High-entropy hafnates demonstrate reduced coefficient of thermal
expansion and thermal conductivity. When corroded at 1300 ℃ , the reaction of（La0.2Gd0.2Ho0.2Er0.2Tm0.2）4Hf3O12 with molten CMAS is more severe and triggers the precipitation of apatite, which mitigates the infiltration of molten CMAS into thermal/environmental barrier coatings. The rare earth hafnate has been regarded as a promising thermal barrier coating material.
2023, 
