A novel (La0.2Ce0.2Sm0.2Eu0.2Gd0.2)PO4 ceramics via high-entropy strategy enabling excellent properties for advanced thermal insulation material

Achieving low thermal conductivity ( κ ) is an ideal goal for porous ceramics in high-temperature thermal insulation applications. In this study, a novel high-entropy (La 0.2 Ce 0.2 Sm 0.2 Eu 0.2 Gd 0.2 )PO 4 (HE (5RE 1/5 )PO 4 ) ceramic possessing the lowest intrinsic thermal conductivity has been screened from 21 kinds of potential high-entropy phosphate with five components. The porous HE (5RE 1/5 )PO 4 ceramics with 30-50 wt% solid loading are fabricated by the particle-stabilized foaming method and the corresponding thermophysical properties are systematically investigated. The porous HE (5RE 1/5 )PO 4 ceramics with 35 wt% solid loading display a better balance between compressive strength (1.51 MPa) and thermal conductivity (0.086 W m −1 K −1 ). Furthermore, porous HE (5RE 1/5 )PO 4 ceramics possess a thermal insulating capability over 878 °C, indicating excellent thermal insulation performance. These excellent characteristics enable porous HE (5RE 1/5 )PO 4 ceramics to be an excellent candidate material for high-temperature thermal insulation applications in the future.