High-entropy (Y0.2Gd0.2Dy0.2Er0.2Yb0.2)2Hf2O7 ceramic: A promising thermal barrier coating material

•(Y0.2Gd0.2Dy0.2Er0.2Yb0.2)2Hf2O7 exhibits great high-temperature phase stability up to 1600 °C and excellent chemical compatibility with Al2O3 even at 1300 °C.○The grain growth rate of high entropy hafnate is more sluggish than that of Y2Hf2O7.○The thermal conductivity of (Y0.2Gd0.2Dy0.2Er0.2Yb0.2)2Hf2O7 (0.73–0.93 W m−1 K−1) is much lower than those of components RE2Hf2O7 and many thermal barrier coating materials.○(Y0.2Gd0.2Dy0.2Er0.2Yb0.2)2Hf2O7 can be as next generation thermal barrier coating material.