Multi-component strategy for remarkable suppression of thermal conductivity in strontium diyttrium oxide: The case of high-entropy Sr (Y0.2Sm0.2Gd0.2Dy0.2Yb0.2)2O4 ceramic

Anti-spinel oxide SrY2O4 has attracted extensive attention as a promising host lattice due to its outstanding high-temperature structural stability and large thermal expansion coefficient (TEC). However, the overhigh thermal conductivity limits its application in the field of thermal barrier coatings. To address this issue, a novel highentropy Sr(Y0.2Sm0.2Gd0.2Dy0.2Yb0.2)(2)O-4 ceramic was designed and synthesized for the first time via the solid-state method. It is found that the thermal conductivity of Sr(Y0.2Sm0.2Gd0.2Dy0.2Yb0.2)(2)O-4 is reduced to 1.61 W center dot m(-1)center dot K-1, 53 % lower than that of SrY2O4 (3.44 W center dot m(-1)center dot K-1) at 1500 degrees C. Furthermore, reasonable TEC (11.53 x10(-6) K-1, 25 degrees C similar to 1500 degrees C), excellent phase stability, and improved fracture toughness (1.92 +/- 0.04 MPa center dot m1/ 2) remained for the high-entropy Sr(Y0.2Sm0.2Gd0.2Dy0.2Yb0.2)(2)O-4 ceramic, making it a promising material for next-generation thermal barrier coatings.