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High-entropy oxides (HEOs) are widely researched as potential materials for thermal barrier coatings (TBCs). However, the relatively low thermal expansion coefficient (TEC) of those materials severely restricts their practical application. In order to improve the poor thermal expansion property and further reduce the thermal conductivity, high-entropy (La0.2Nd0.2Sm0.2Eu0.2Gd0.2)2Ce2O7 is designed and synthesized in this work. The as-prepared multicomponent material is formed in a simple disordered fluorite structure due to the high-entropy stabilization effect. Notably, it exhibits a much higher TEC of approximately 12.0 × 10-6 K-1 compared with those of other high-entropy oxides reported in the field of TBCs. Besides, it presents prominent thermal insulation behavior with a low intrinsic thermal conductivity of 0.92 W·m-1·K-1 at 1400 ℃, which can be explained by the existence of high concentration oxygen vacancies and highly disordered arrangement of multicomponent cations in the unique high-entropy configuration. Through high-temperature in-situ X-ray diffraction (XRD) measurement, this material shows excellent phase stability up to 1400 ℃. Benefiting from the solid solution strengthening effect, it shows a higher hardness of 8.72 GPa than the corresponding single component compounds. The superior thermo-physical performance above enables (La0.2Nd0.2Sm0.2Eu0.2Gd0.2)2Ce2O7 a promising TBC material.


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High-entropy (La0.2Nd0.2Sm0.2Eu0.2Gd0.2)2Ce2O7: A potential thermal barrier material with improved thermo-physical properties

Show Author's information Yun XUEa,bXiaoqin ZHAOa,bYulong ANa,b( )Yijing WANGa,bMeizhen GAOcHuidi ZHOUa,bJianmin CHENa,b
Key Laboratory of Science and Technology on Wear and Protection of Materials, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
Key Lab for Magnetism and Magnetic Materials of MOE, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China

Abstract

High-entropy oxides (HEOs) are widely researched as potential materials for thermal barrier coatings (TBCs). However, the relatively low thermal expansion coefficient (TEC) of those materials severely restricts their practical application. In order to improve the poor thermal expansion property and further reduce the thermal conductivity, high-entropy (La0.2Nd0.2Sm0.2Eu0.2Gd0.2)2Ce2O7 is designed and synthesized in this work. The as-prepared multicomponent material is formed in a simple disordered fluorite structure due to the high-entropy stabilization effect. Notably, it exhibits a much higher TEC of approximately 12.0 × 10-6 K-1 compared with those of other high-entropy oxides reported in the field of TBCs. Besides, it presents prominent thermal insulation behavior with a low intrinsic thermal conductivity of 0.92 W·m-1·K-1 at 1400 ℃, which can be explained by the existence of high concentration oxygen vacancies and highly disordered arrangement of multicomponent cations in the unique high-entropy configuration. Through high-temperature in-situ X-ray diffraction (XRD) measurement, this material shows excellent phase stability up to 1400 ℃. Benefiting from the solid solution strengthening effect, it shows a higher hardness of 8.72 GPa than the corresponding single component compounds. The superior thermo-physical performance above enables (La0.2Nd0.2Sm0.2Eu0.2Gd0.2)2Ce2O7 a promising TBC material.

Keywords:

high-entropy oxides (HEOs), (La0.2Nd0.2Sm0.2Eu0.2Gd0.2)2Ce2O7, defective fluorite structure, thermal expansion coefficient (TEC), thermal conductivity, thermal barrier coating (TBC)
Received: 27 July 2021 Revised: 06 December 2021 Accepted: 10 December 2021 Published: 03 March 2022 Issue date: April 2022
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Publication history
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Publication history

Received: 27 July 2021
Revised: 06 December 2021
Accepted: 10 December 2021
Published: 03 March 2022
Issue date: April 2022

Copyright

© The Author(s) 2021.

Acknowledgements

This research was financially supported by Youth Innovation Promotion Association (No. 2014378) for Chinese Academy of Sciences. The authors are grateful to the constructive comments of the reviewers.

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