Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7993209 | Journal of Alloys and Compounds | 2018 | 36 Pages |
Abstract
The effect of the sintering holding time on the microstructure and thermoelectric properties of Bi0.4Sb1.6Te3 prepared by pulse-current sintering under cyclic uniaxial pressure was investigated. The sintering was performed at 400â¯Â°C under a cyclic pressure of 0â¯MPa and 100â¯MPa, and the holding time was varied from 0 to 60â¯min. The microstructure of samples, including grain size, hexagonal c-plane texture, and high-angle grain boundary, changed with holding time, that is, grain size and c-plane texture were enhanced and the high-angle grain boundary was reduced with increasing holding time. The thermoelectric properties changed corresponding to the change in the microstructures. The Seebeck coefficient was independent of the sintering parameters and had a value of approximately 200â¯Î¼V/K. Nevertheless, electrical resistivity decreased with holding time because of the increase in the c-plane texture. As a result, the power factor was enhanced with increasing holding time. In contrast, thermal conductivity was insensitive with the holding time and had almost constant value. As a result, a dimensionless figure of merit of approximately 1â¯at 300â¯K was achieved with a large power factor of 4.3â¯Ãâ¯10â3â¯W/K2m. Therefore, in the PCS-cyclic process, the holding time is an important sintering parameter for controlling the microstructure and electrical properties of Bi0.4Sb1.6Te3 thermoelectric materials.
Related Topics
Physical Sciences and Engineering
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Metals and Alloys
Authors
Ayako Suzuki, Hiroyuki Kitagawa, Shota Ido, Anh Hoang Pham, Shigekazu Morito, Takao Etoh, Kotaro Kikuchi,