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Investigation of homogeneity in microstructure and thermoelectric properties at various positions in high-thickness sintered bulks of p-type 20%Bi2Te3–80%Sb2Te3 alloys

Title
Investigation of homogeneity in microstructure and thermoelectric properties at various positions in high-thickness sintered bulks of p-type 20%Bi2Te3–80%Sb2Te3 alloys
Authors
Madavali, BabuLee, Chul-HeeHan, Jin-GuKim, Dong HwanKim, Jong TaeSong, GianLee, Jin KyuHong, Soon-Jik
DGIST Authors
Madavali, Babu; Lee, Chul-Hee; Han, Jin-Gu; Kim, Dong Hwan; Kim, Jong Tae; Song, Gian; Lee, Jin Kyu; Hong, Soon-Jik
Issue Date
2021-05
Citation
Journal of Materials Science: Materials in Electronics
Type
Article
Keywords
LARGE-SCALE PRODUCTIONPERFORMANCESB
ISSN
0957-4522
Abstract
Thermoelectric devices are environmentally friendly renewable energy sources that use waste heat to generate electricity. So far, p-type Bi–Sb–Te-based alloys with high thermoelectric properties were fabricated using low-dimensional and single growth methods as small-scale, laboratory-grown samples. However, large-scale fabrication processes are required for commercial applications of thermoelectric devices. In this work, large amounts (2–3 kg) of p-type 20%Bi2Te3–80%Sb2Te3 alloy powders were fabricated using the gas atomization (GA) process under an inert gas atmosphere. Subsequently, a large-scale sample, 64 mm thick and 25 mm in diameter, was consolidated from the as-fabricated GA powders using spark plasma sintering at 673 K. The homogeneity of the microstructure, density, thermoelectric properties, and mechanical properties of the high-thickness sintered bulk were systematically investigated at various positions. The EBSD texture analysis revealed that an almost similar microstructure existed in all positions of the bulk sample, which was comprised of a mixture of coarse grains and fine grains randomly distributed throughout the matrix. The peak electrical conductivity of 1100 Ω−1 cm−1 was obtained from the top position of the thick sample, which had a relatively higher carrier mobility. The maximum power factor of 3.96 mW/mK2 was achieved by the top part of the specimen, because of its higher electrical conductivity. The lowest thermal conductivity of 0.964 W/mK at 350 K was obtained from the bottom part of the specimen. As a result, the maximum figure of merit, ZT of 1.25 was achieved in the bottom position of the high-thickness sample. Homogeneous (within 5% of variation) thermoelectric transport properties were observed throughout the fabricated high-thickness sintered sample, regardless of position. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
URI
http://hdl.handle.net/20.500.11750/13752
DOI
10.1007/s10854-021-06178-w
Publisher
Springer
Related Researcher
Files:
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Collection:
Division of Nanotechnology1. Journal Articles


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