Revolutionary High-entropy Zr-Y-Yb-Ta-Nb-O Oxides for Next Generation Thermal Barrier Coating Applications

Abstract

We report a revolutionary ceramic material with exceptional high temperature stability and superior thermo-mechanical properties for next generation thermal barrier coatings (TBCs) for aeroengines. The multicomponent oxides (Zr1 − 4xYxYbxTaxNbxO2) designed via a high entropy concept could exhibit a double tetragonal phase. The optimized composition breaks the limitation of intrinsic brittleness in previously reported TBC candidate materials and shows a superior toughness up to ~ 4.59 MPa m1/2 due to ferroelastic and phase transformation toughening mechanisms. It also shows a remarkable high temperature stability at 1600 ºC, which is almost 400 ºC higher than the state-of-the-art yttria stabilized zirconia TBC material. In addition, it also exhibits a significantly lower thermal conductivity (~ 1.37 W∙m− 1∙K− 1 at 900 ºC) and a higher coefficient of thermal expansion (~ 11.3 × 10− 6 K− 1 at 1000 ºC), as well as excellent corrosion resistance to molten silicate (~ 2.9 µm/h at 1300 ºC). This work provides a new approach to design ceramics by extending the high-entropy concept to both medium-entropy and high-entropy compositions searching for multifunctional properties.