Investigation on improving corrosion resistance of rare earth pyrosilicates by high-entropy design with RE-doping

To combine the advantages of the thermal expansion coefficient and excellent corrosion resistance to calcium-magnesium-alumino-silicate (CMAS), two types of high-entropy pyrosilicates ((Yb0.2Y0.2Lu0.2Ho0.2Er0.2)2Si2O7 and (Yb0.25Lu0.25Ho0.25Er0.25)2Si2O7) and two single-component pyrosilicates (Yb2Si2O7 and Lu2Si2O7) were prepared by the solid-phase method. CMAS corrosion resistance test results showed that the high-entropy pyrosilicates that form a stable β phase could precipitate apatite (Ca2RE8(SiO4)6O2) more easily than Yb2Si2O7 and Lu2Si2O7 during the corrosion process to protect the block from CMAS. The results provide a theoretical basis for the selection of rare earth elements in high-entropy pyrosilicate according to the radius of different rare earth cation.