High-entropy rare-earth disilicate (Lu0.2Yb0.2Er0.2Tm0.2Sc0.2)2Si2O7: A potential environmental barrier coating material

A new high-entropy ceramic (Lu0.2Yb0.2Er0.2Tm0.2Sc0.2)2Si(2)O(7) ((5RE(0.2))(2)Si2O7) was proposed as a potential environmental barrier coating (EBC) material for ceramics matrix composites in this work. Experimental results showed that the (5RE(0.2))(2)Si2O7 synthesized by solid-phase sintering was a monoclinic solid solution and had good phase stability proved by no obvious absorption/exothermic peak in the DSC curve from room temperature to 1400 & DEG;C. It performed a lower coefficient of thermal expansion (2.08 x10(-6)-4.03 x10(-6) & DEG;C-1) and thermal conductivity (1.76-2.99 Wem(-1)e & DEG;C-1) compared with the five single principal RE2Si2O7. In water vapor corrosion tests, (5RE(0.2))(2)Si2O7 also exhibited better water vapor corrosion resistance attributed to the multiple doping effects. The weight loss was only 3.1831 x 10(-5) gecm(-2) after 200 h corrosion at 1500 & DEG;C, which was lower than that of each single principal RE2Si2O7. Therefore, (5RE(0.2))(2)Si2O7 could be regarded as a remarkable candidate for EBCs.

Automated summary

A new high-entropy ceramic (5RE(0.2))(2)Si2O7 was proposed as a potential environmental barrier coating material for ceramics matrix composites. The (5RE(0.2))(2)Si2O7 showed good phase stability, low coefficient of thermal expansion and thermal conductivity, and exhibited better water vapor corrosion resistance.