Tailoring thermal and mechanical properties of rare earth niobates by coupling entropy and composite engineering |
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| Affiliation: | 1. State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;2. Productivity Center of Building Materials Industry, Beijing 100024, China;3. School of Statistics, Beijing Normal University, Beijing 100091, China;1. Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081, PR China;2. The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, PR China;1. Department of Extreme Environmental Coatings, Korea Institute of Materials Science, Changwon, Gyeongnam 51508, Republic of Korea;2. Department of Materials Convergence and System Engineering, Changwon National University, Changwon, Gyeongnam 51140, Republic of Korea;3. Research Center of Modern Surface and Interface Engineering, Anhui University of Technology, Maanshan 243002, China;4. BGRIMM Technology Group, Beijing 100160, China;1. National United Engineering Laboratory for Advanced Bearing Tribology, Henan University of Science and Technology, Luoyang 471023, China;2. School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471023, China;3. State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China;4. School of Environmental Engineering and Chemistry, Luoyang Institute of Science and Technology, Luoyang 471023, China;1. School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou 510006, China;2. School of Material Science and Energy Engineering, Foshan University, Foshan 528000, China;3. Hunan Key Laboratory of applied Enviromental Photocatalysis, Changsha University, Changsha 410022, China |
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| Abstract: | In this paper, a series of high-entropy rare earth niobates, including fluorite RE3NbO7 (HE317), monoclinic RENbO4 (HE114) and RENbO4/RE3NbO7 composite (HE-composite), are prepared via solid state reaction, following by a study about their thermal and mechanical properties. The high-entropy rare earth niobates exhibit excellent phase stability after thermally exposed to 1300 °C for 100 h, indicating entropy can stabilized high-entropy rare earth niobates. Compared with the single element rare earth niobates, high-entropy rare earth niobates have higher fracture toughness and hardness. The high-entropy RENbO4/RE3NbO7 composite has the best mechanical properties, with a fracture toughness of 2.71 ± 0.17 MPa·m1/2 and hardness of 9.46 ± 0.24 GPa, respectively. The high-entropy niobates exhibit high coefficients of thermal expansion which is close to 7 wt% Y2O3 stabilized ZrO2. It is also proved that the configurational entropy has little effect on the critical temperature from monoclinic to tetragonal phase transition. The thermal conductivity of HE-composite is lower than HE114, indicating the combination of HE114 and H317 is a more efficient strategy to decrease the thermal conductivity of HE114 than entropy engineering. |
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| Keywords: | High entropy oxides Composite Rare earth niobates TBCs |
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