Grain orientation evolution and multi-scale interfaces enhanced thermoelectric properties of textured Sr0.9La0.1TiO3 based ceramics
Ping Zhang, Mengjie Qin, Zhihao Lou, Shuyao Cao, Lingyun Gong, Jie Xu, Michael J. Reece, Haixue Yan, Z. Dashevsky, Feng Gao
Abstract
Sr 0.9 La 0.1 TiO 3 based textured ceramics (SLTT-S3T) with a texture fraction of 0.81 are successfully fabricated by the reactive template grain growth method, in which Sr 0.9 La 0.1 TiO 3 /20 wt%Ti was used as matrix and 10 wt% plate-like Sr 3 Ti 2 O 7 template seeds were used as templates. The phase transition, microstructure evolution, and the anisotropic thermoelectric properties of SLTT-S3T ceramics were investigated. The results show that the ceramics are mainly composed of Sr 0.9 La 0.1 TiO 3 and rutile TiO 2 phases. Grains grow with a preferred orientation along ( h 00). A maximum ZT of 0.26 at 1073 K was achieved in the direction perpendicular to the tape casting direction. The low lattice thermal conductivity of 1.9 W/(m K) at 1073 K was obtained decreased by 34%, 40%, and 38% compared with non-textured, SrTiO 3 and Sr 0.9 La 0.1 TiO 3 ceramics prepared by the same process, can be attributed to the enhanced phonon scattering by the complex multi-scale boundaries and interfaces. This work provides a strategy of microstructural design for thermoelectric oxides to decrease intrinsic lattice thermal conductivity and further regulate thermoelectric properties via texture engineering.