A promising (Yb_0.2Tm_0.2Lu_0.2Sc_0.2Er_0.2)₂Si₂O₇ with excellent thermophysical properties for thermal environmental barrier coatings material

Aiming at the development of thermal environmental barrier coatings (TEBCs) material, the factor of grain size is introduced into the high-entropy rare-earth disilicate for the first time. The (Yb_0.2Tm_0.2Lu_0.2Sc_0.2Er_0.2)₂Si₂O₇ with smaller grain size was prepared by one-step pressureless sintering method. Results of thermal conductivity and coefficient of thermal expansion (CTE) reveal that thermal conductivity of (Yb_0.2Tm_0.2Lu_0.2Sc_0.2Er_0.2)₂Si₂O₇ bulk material is lower than that all existing EBCs and even most TBCs and potential TEBCs material, which is 0.686 W m⁻¹ °C⁻¹ at 1300 °C. Excellent thermophysical properties indicate that designed (Yb_0.2Tm_0.2Lu_0.2Sc_0.2Er_0.2)₂Si₂O₇ with small grain size can be used as a promising TEBCs material.