Investigation of thermophysical properties of ZrO2-Sm3TaO7 ceramics

• Main Authors: Ying Zhou, Guoyou Gan, Zhenhua Ge, Jing Feng, Song Peng
• Format: Article
• Language: English
• Published: Taylor & Francis Group 2021-04-01
• Series: Journal of Asian Ceramic Societies
• Subjects: zro2-sm3tao7 ceramics; solid-solution mechanism; thermophysical properties
• Online Access: http://dx.doi.org/10.1080/21870764.2021.1907025

This study investigates rare earth RE3TaO7 ceramics and shows that these materials may be optimal for thermal barrier coatings. ZrO2-Sm3TaO7 ceramics were prepared through a solid-state reaction. X-ray diffusion and structural refinement revealed a phase structure with an ordered orthorhombic phase for the Ccmm space group. The degree of structural disorder increased with increasing ZrO2 content. Gaussian function fitting of the oxygen 1s X-ray photoelectron spectra showed that the Sm3+ and Ta5+ ions were replaced by Zr4+ ions. At high temperatures, 8 mol% ZrO2-Sm3TaO7 has a high thermal expansion coefficient (10.9 × 10−6 K−1). The thermal conductivities of ZrO2-Sm3TaO7 (1.17 − 1.75 W·m−1 K−1) are lower than those of 7–8 wt.% yttria-stabilized zirconia, while those of 2% ZrO2-Sm3TaO7 are the lowest. The oxygen vacancies maintain the charge in equilibrium and enhance phonon scattering while decreasing the thermal conductivity. These results indicate that Sm3TaO7 can be used as a TBC.