Improvement of thermal insulating performance via entropy-stabilization in rare-earth zirconate structures

Thermal barrier coating (TBC) materials employ ceramics with low thermal conductivity and excellent thermal durability. Recently, the gas turbine market has been increasing demand for a thermally insulating material applicable at higher operating temperatures above 1200 °C for greater thermal conversion efficiency. In this study, synthesized high-entropy A2Zr2O7 zirconate ceramics incorporated five cations of a similar ionic radius into the A3+ cation site through a conventional solid-state reaction, and their superior thermophysical properties demonstrate. The HEO ceramics exhibited overall low thermal conductivity (from room temperature to 1000 °C) due to inducing lattice distortion in the crystal structure. In addition, divalent cations were added to the A3+ cation site to increase the oxygen vacancy at the structure, thereby suppressing the heat transfer caused by phonon. A2Zr2O7 zirconate HEOs show enhanced thermal barrier performance than yttria-stabilized zirconia (YSZ), conventional TBC material, demonstrating a possibility of application as next-generation TBC materials.