High-entropy (La0.2Nd0.2Y0.2Yb0.2Lu0.2)2Zr2O7 ceramic: A novel dual-phase high-entropy ceramic

Thermal barrier coating (TBC) materials, used to protect high-temperature components in gas turbines, require properties such as low thermal conductivity, resistance to sintering, and high-temperature stability. In this study, a novel defect fluorite-phase high-entropy zirconate powder(La0.2Nd0.2Y0.2Yb0.2Lu0.2)2Zr2O7 was synthesized using solution precursor plasma spraying (SPPS), which exhibits high sphericity and uniform composition distribution. The(La0.2Nd0.2Y0.2Yb0.2Lu0.2)2Zr2O7 ceramic bulk was sintered from SPPS prepared powder by pressureless sintering. The phase structures, thermal and mechanical properties of the samples were investigated using various techniques. The results indicated that the(La0.2Nd0.2Y0.2Yb0.2Lu0.2)2Zr2O7 ceramic bulk has a defect fluorite-pyrochlore dual-phase structure and exhibits a low thermal conductivity about 1.09 W & sdot;m-1 & sdot;K-1 at 1400 degrees C. Compared to La2Zr2O7 ceramic,(La0.2Nd0.2Y0.2Yb0.2Lu0.2)2Zr2O7 exhibits a slower grain growth rate of 3.6 x 10-4 mu m/h, it also displays superior mechanical properties, including high hardness (10.03 +/- 0.32 GPa) and fracture toughness KIC (1.04 +/- 0.17 MPa & sdot;m1/2). These outstanding thermal and mechanical properties make (La0.2Nd0.2Y0.2Yb0.2Lu0.2)2Zr2O7 a highly promising candidate for TBC applications.