Anisotropy of the thermoelectric figure of merit (ZT) in textured Ca3Co4O9 ceramics prepared by using a spark plasma sintering process

Chang Hyun Lim, Won Seon Seo, Soonil Lee, Young Soo Lim, Jong Young Kim, Hyung Ho Park, Soon Mok Choi, Kyu Hyoung Lee, Kyeongsoon Park

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6 Citations (Scopus)

Abstract

Textured Ca3Co4O9 ceramics were prepared by spark plasma sintering (SPS) from commercial CaCO3 and Co3O4 powders to investigate the thermoelectric anisotropy of Ca3Co4O9. The degree of orientation of the textured specimens was evaluated by using the Lotgering factor method, and the SPS process was confirmed to be an effective technology to prepare textured Ca3Co4O9 ceramics. Both the power factors and the thermal conductivities were measured in two different directions, parallel (out-of-plane) and perpendicular (in-plane) to the SPS press axis. The difference in anisotropy between the electrical conductivity and the thermal conductivity was investigated for the textured Ca3Co4O9 ceramics. The maximum figure of merit (ZT) value along the direction perpendicular to the SPS press axis was more than 20% higher than it was along the direction parallel to the SPS press axis. It is noted that the strong thermoelectric anisotropy can give rise to an overestimates of ZT when preparing samples in different directions for power factor and thermal conductivity measurements.

Original languageEnglish
Pages (from-to)794-799
Number of pages6
JournalJournal of the Korean Physical Society
Volume66
Issue number5
DOIs
Publication statusPublished - 2015 Jan 1

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All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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