Marked reduction in the thermal conductivity of (La0.2Gd0.2Y0.2Yb0.2Er0.2)2Zr2O7 high-entropy ceramics by substituting Zr4+ with Ti4
The (La0.2Gd0.2Y0.2Yb0.2Er0.2)2(Zr1-xTix)2O7 (x = 0–0.5) high-entropy ceramics were successfully prepared by a solid state reaction method and their structures and thermo-physical properties were investigated. It was found that the high-entropy ceramics demonstrate pure pyrochlore phase with the com...
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Published in | Ceramics international Vol. 48; no. 7; pp. 9602 - 9609 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Elsevier Ltd
01.04.2022
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Subjects | |
Online Access | Get full text |
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Summary: | The (La0.2Gd0.2Y0.2Yb0.2Er0.2)2(Zr1-xTix)2O7 (x = 0–0.5) high-entropy ceramics were successfully prepared by a solid state reaction method and their structures and thermo-physical properties were investigated. It was found that the high-entropy ceramics demonstrate pure pyrochlore phase with the composition of x = 0.1–0.5, while (La0.2Gd0.2Y0.2Yb0.2Er0.2)2Zr2O7 shows the defective fluorite structure. The sintered high-entropy ceramics are dense and the grain boundaries are clean. The grain size of high-entropy ceramics increases with the Ti4+ content. The average thermal expansion coefficients of the (La0.2Gd0.2Y0.2Yb0.2Er0.2)2(Zr1-xTix)2O7 high-entropy ceramics range from 10.65 × 10−6 K−1 to 10.84 × 10−6 K−1. Importantly, the substitution of Zr4+ with Ti4+ resulted in a remarkable decrease in thermal conductivity of (La0.2Gd0.2Y0.2Yb0.2Er0.2)2(Zr1-xTix)2O7 high-entropy ceramics. It reduced from 1.66 W m−1 K−1 to 1.20 W m−1 K−1, which should be ascribed to the synergistic effects of mass disorder, size disorder, mixed configuration entropy value and rattlers. |
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ISSN: | 0272-8842 1873-3956 |
DOI: | 10.1016/j.ceramint.2021.12.158 |