A new high entropy rare earth disilicate ceramic (Lu1/8Yb1/8Sc1/8Er1/8Y1/8Ho1/8Dy1/8Tb1/8)2Si2O7: high temperature corrosion of water vapor and molten calcium–magnesium–aluminosilicate (CMAS)

A new β-(Lu1/8Yb1/8Sc1/8Er1/8Y1/8Ho1/8Dy1/8Tb1/8)2Si2O7 ((8RE1/8)2Si2O7) disilicate was prepared using a solid reaction process to protect SiCf/SiC CMC component materials. The thermal properties and corrosion resistance of (8RE1/8)2Si2O7 were systematically studied. Experimental results showed that (8RE1/8)2Si2O7 exhibited lower thermal conductivity than that of one-component silicate materials, only 1.80 (W•m-1•K-1) at 1000 °C. Meanwhile, (8RE1/8)2Si2O7 also exhibited superior water vapor and CMAS corrosion resistance. The weight loss was 1.05 × 10-4 g/cm2 after 200 h corrosion at 1400 °C. When it interacted with CMAS at 1300 ℃ for 48 h, the reaction layer was only 16 μm. Therefore, (8RE1/8)2Si2O7 could be regarded as a remarkable candidate for T/EBC.