Design and synthesis of single phase Hf0.25Zr0.25Ce0.25Y0.125Si0.125O2-δ high-entropy ceramics

We design and synthesise a new high-entropy ceramic Hf0.25Zr0.25Ce0.25Y0.125Si0.125O2-delta through a hybrid mixing of non-metal and metal atoms. First-principles calculations predict the thermal stability of the single-crystal phase at high temperatures. XRD and EDS mapping confirm a single cubic fluorite phase with a uniform elemental distribution. In-situ high-temperature XRD shows that the phase is stable with no phase separation or secondary phases. The measured mechanical and thermal properties are comparable with reported high-entropy fluorite oxides. Our results add to the compositional space of high-entropy ceramics for a wide range of applications from thermal insulators to electronics. (C) 2022 Elsevier B.V. All rights reserved.