Multicomponent high‐entropy Zr‐Y‐Yb‐Ta‐Nb‐O oxides for next‐generation thermal barrier coating applications

Abstract We report a multicomponent ceramic material with exceptional high‐temperature stability and superior thermo‐mechanical properties for next‐generation thermal barrier coatings (TBCs) for aeroengines. The multicomponent oxides (Zr 1‐4 x Y x Yb x Ta x Nb x O 2 ) designed via a high‐entropy concept could exhibit a double tetragonal phase. The optimized composition breaks the limitation of intrinsic brittleness in mostly previously reported TBC candidate materials and shows a superior toughness up to ~4.59 MPa m 1/2 due to ferroelastic and phase transformation toughening mechanisms. It also shows a remarkable high‐temperature stability at 1600°C, which is almost 400°C 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°C) and a higher coefficient of thermal expansion (~11.3 × 10 −6 K −1 at 1000°C), as well as excellent corrosion resistance to molten silicate (~2.9 μm/h at 1300°C). This work provides a new sight to design ceramics by extending the high‐entropy concept to both medium‐entropy and high‐entropy compositions searching for multifunctional properties.