Low thermal conductivity and anisotropic thermal expansion of ferroelastic (Gd1−xYx)TaO4 ceramics

Autor: Chenkai Qu, Lin Chen, Liang Lv, Yuncheng Wang, Xiaolan Ji, Haitao Yun, Chaoqun Su, Jing Feng
Rok vydání: 2022
Předmět:
Zdroj: Journal of Advanced Ceramics. 11:1696-1713
ISSN: 2227-8508
2226-4108
Popis: In this paper, (Gd1−xYx)TaO4 ceramics had been fabricated by solid-phase synthesis reaction. Each sample was found to crystallize in a monoclinic phase by X-ray diffraction (XRD). The properties of (Gd1−xYx)TaO4 were optimized by adjusting the ratio of Gd/Y. (Gd1−xYx)TaO4 had a low high-temperature thermal conductivity (1.37–2.05 W·m−1·K−1), which was regulated by lattice imperfections. The phase transition temperature of the (Gd1−xYx)TaO4 ceramics was higher than 1500 °C. Moreover, the linear thermal expansion coefficients (TECs) were 10.5×10−6 K−1 (1200 °C), which was not inferior to yttria-stabilized zirconia (YSZ) (11×10−6 K−1, 1200 °C). (Gd1−xYx)TaO4 had anisotropic thermal expansion. Therefore, controlling preferred orientation could minimize the TEC mismatch when (Gd1−xYx)TaO4 coatings were deposited on different substrates as thermal barrier coatings (TBCs). Based on their excellent properties, it is believed that the (Gd1−xYx)TaO4 ceramics will become the next generation of high-temperature thermal protective coatings.
Databáze: OpenAIRE
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