Excellent CMAS Corrosion Resistance of a Novel Multicomponent High-Entropy Rare Earth (Yb0.25Sc0.25Er0.25Tm0.25)2Si2O7 Disilicate

A novel high-entropy rare earth (Yb0.25Sc0.25Er0.25Tm0.25)2Si2O7 or 4(YSET)0.25 disilicate was fabricated through a solid-solution method to protect the underlying SiC substrate from harsh environment at elevated temperature. XRD analysis showed that the newly fabricated 4(YSET)0.25 exactly matched with the constituent base Yb2Si2O7 having a single stable beta phase. The microstructure analysis showed that the powder was uniformly mixed. A CMAS exposure test was done to check the corrosion properties of 4(YSET)0.25 at 1300 degrees C for 4 h and 48 h. The 4(YSET)0.25 showed better resistance against CMAS after 48 h at 1300 degrees C, and a negligible amount of Ca was able to penetrate toward the 4(YSET)0.25 substrate. The overall performance of 4(YSET)0.25 against CMAS was far better than their single constituent elements.