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The high-entropy rare-earth zirconate ((La0.2Nd0.2Sm0.2Gd0.2Yb0.2)2Zr2O7, 5RE2Zr2O7 HE- REZs) ceramics were successfully prepared by a new high-speed positive grinding strategy combined with solid-state reaction method. The microstructure, crystal structure, phase composition, and thermophysical and mechanical properties of the samples were systematically investigated through various methods. Results indicate that the samples have a single-phase defect fluorite-type crystal structure with excellent high-temperature thermal stability. The as-prepared samples also demonstrate low thermal conductivity (0.9-1.72 W·m-1·K-1 at 273-1273 K) and high coefficient of thermal expansion (CTE, 10.9 × 10-6 K-1 at 1273 K), as well as outstanding mechanical properties including large Young’s modulus (E = 186-257 GPa) and high fracture toughness (KIC). Furthermore, the formation possibility of the as-prepared samples was verified through the first-principles calculations, which suggested the feasibility to form the 5RE2Zr2O7 HE-REZs in the thermodynamic direction. Therefore, in view of the excellent multifunctional properties exhibited by the as-prepared 5RE2Zr2O7 HE-REZs, they have great potential applications in next-generation thermal-barrier coatings (TBCs).


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High-entropy rare-earth zirconate ceramics with low thermal conductivity for advanced thermal-barrier coatings

Show Author's information Debao LIUaBaolu SHIaLiyan GENGbYiguang WANGaBaosheng XUa( )Yanfei CHENa
Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China
Shanghai Space Propulsion Technology Research Institute, Shanghai 201109, China

Abstract

The high-entropy rare-earth zirconate ((La0.2Nd0.2Sm0.2Gd0.2Yb0.2)2Zr2O7, 5RE2Zr2O7 HE- REZs) ceramics were successfully prepared by a new high-speed positive grinding strategy combined with solid-state reaction method. The microstructure, crystal structure, phase composition, and thermophysical and mechanical properties of the samples were systematically investigated through various methods. Results indicate that the samples have a single-phase defect fluorite-type crystal structure with excellent high-temperature thermal stability. The as-prepared samples also demonstrate low thermal conductivity (0.9-1.72 W·m-1·K-1 at 273-1273 K) and high coefficient of thermal expansion (CTE, 10.9 × 10-6 K-1 at 1273 K), as well as outstanding mechanical properties including large Young’s modulus (E = 186-257 GPa) and high fracture toughness (KIC). Furthermore, the formation possibility of the as-prepared samples was verified through the first-principles calculations, which suggested the feasibility to form the 5RE2Zr2O7 HE-REZs in the thermodynamic direction. Therefore, in view of the excellent multifunctional properties exhibited by the as-prepared 5RE2Zr2O7 HE-REZs, they have great potential applications in next-generation thermal-barrier coatings (TBCs).

Keywords:

high-entropy rare-earth zirconates (HE-REZs), first-principles calculations, thermal conductivity, thermal stability, Young’s modulus, thermal-barrier coatings (TBCs)
Received: 21 November 2021 Revised: 16 March 2022 Accepted: 19 March 2022 Published: 11 May 2022 Issue date: June 2022
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Publication history

Received: 21 November 2021
Revised: 16 March 2022
Accepted: 19 March 2022
Published: 11 May 2022
Issue date: June 2022

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© The Author(s) 2022.

Acknowledgements

This work is supported by the National Science and Technology Major Project (2017-VI-0020-0093) and the National Natural Science Foundation of China (12090031). By the way, the authors would like to thank Jinghua XU from Shiyanjia Lab (www.shiyanjia.com) for the TG/DSC analysis. The authors would like to thank the Analysis and Testing Center of Beijing Institute of Technology.

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