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In this work, we have successfully fabricated a novel high-entropy rare-earth zirconate (La0.2Nd0.2Sm0.2Gd0.2Yb0.2)2Zr2O7 (5RE2Zr2O7) ceramics and its counterparts by using a new high-speed grinding strategy combined with typical solid-state reaction method. The X-ray diffraction (XRD) and Raman spectroscopy analysis indicated that the as-prepared 5RE2Zr2O7 ceramics performed single-phase defect fluorite-type structures with highly sintering resistant and excellent thermal stability. The possibility of formation of 5RE2Zr2O7 was verified via first-principles calculations. Meanwhile, the phase structure, thermophysical and mechanical properties of the samples were systematically investigated. The results showed that the 5RE2Zr2O7 ceramics demonstrated lower thermal conductivity (0.9-1.72 W·m-1·K-1) and higher thermal expansion coefficients (10.9 × 10-6 K-1 at 1273 K) than its counterparts. Furthermore, the 5RE2Zr2O7 ceramics presented outstanding mechanical properties including large Young’s modulus (186-257 GPa), higher fracture toughness and lower brittleness index than that of YSZ. Therefore, in view of various excellent properties, the as-prepared 5RE2Zr2O7 ceramics possess great potential for applications in the field of thermal barrier coatings.

A novel porous La2Zr2O7 ceramic prepared by combining a sol-gel template method and high-temperature calcination process. The structural evolution and crystallisation behaviour of the samples were systematically characterized using SEM, XRD, TEM and Raman spectroscopy. The results indicated that the as-prepared porous La2Zr2O7 ceramic had a typical nanoparticles assembling and mesoporous structure with single-phase pyrochlore crystal structure. Meanwhile, the as-prepared porous La2Zr2O7 ceramic presented an ultralow room temperature thermal conductivity of 0.07 W/(m·K), high specific surface areas of 325.17 m2/g and a relatively high compressive strength of 11.95 MPa. What’s more, the as-prepared porous La2Zr2O7 ceramic possessed ideal photocatalytic activity owing to the unique 3-D porous structure, high crystallinity and large surface area. These reported studies are proposing some new insight to improve porous rare-earth zirconates ceramic for thermal insulation and dye degradation applications.