Jun Wang, Qianqian Jin, Jianbo Song, Di Zhang, Bin Xu, Zhiyi Ren, Meng Wang, Shixiao Yan, Xiaoliang Sun, Chi Liu, Xiaoyu Chong, Jing Feng
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引用次数: 0
Abstract
Thermal barrier coatings (TBCs) materials can improve energy conversion efficiency and reduce fossil fuel use. Herein, the novel rare earth tantalates RETaO4, as promising candidates for TBCs, were reassembled into multi-component solid solutions with a monoclinic structure to further depress the thermal conductivity via an entropy strategy. The formation mechanisms of oxygen vacancy defects, dislocations and ferroelastic domains associated with thermal conductivity are demonstrated by aberration-corrected scanning transmission electron microscopy. Compared to single-RE RETaO4 and 8YSZ, the intrinsic thermal conductivity of (5RE1/5)TaO4 was decreased by 35% ~ 47% and 57% ~ 69% at 1200°C, respectively, which is likely attributed to the multi-scale phonon scattering from Umklapp phonon–phonon, point defects, domain structures and dislocations. and low-temperature thermal conductivity are negatively correlated, as are E/κ and high-temperature thermal conductivity. Meanwhile, the high defects' concentration and lattice distortion in high-entropy ceramics enhances the scattering of transverse-wave phonons and reduces the transverse-wave sound velocity, leading to a decrease in the thermal conductivity and Young's modulus. In addition, 5HEC-1 has ultra-low thermal conductivity, moderate thermal expansion coefficients and high hardness among the three five-component high-entropy samples. Thus, 5HEC-1 with superior thermal barrier and mechanical properties can be used as a promising thermal insulating material.
期刊介绍:
Journal of Advanced Ceramics is a single-blind peer-reviewed, open access international journal published on behalf of the State Key Laboratory of New Ceramics and Fine Processing (Tsinghua University, China) and the Advanced Ceramics Division of the Chinese Ceramic Society.
Journal of Advanced Ceramics provides a forum for publishing original research papers, rapid communications, and commissioned reviews relating to advanced ceramic materials in the forms of particulates, dense or porous bodies, thin/thick films or coatings and laminated, graded and composite structures.