Fabrication of highly textured Ca3Co4O9 ceramics with controlled density and high thermoelectric power factors
| Autor: | Rina Shimonishi, Manabu Hagiwara, Shinobu Fujihara |
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| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Materials science Fabrication 02 engineering and technology 021001 nanoscience & nanotechnology Thermoelectric materials 01 natural sciences Grain growth Electrical resistivity and conductivity visual_art Seebeck coefficient 0103 physical sciences Thermoelectric effect Materials Chemistry Ceramics and Composites visual_art.visual_art_medium Relative density Ceramic Composite material 0210 nano-technology |
| Zdroj: | Journal of the European Ceramic Society. 40:1338-1343 |
| ISSN: | 0955-2219 |
| DOI: | 10.1016/j.jeurceramsoc.2019.11.077 |
| Popis: | Ca3Co4O9 ceramics have been studied as an alternative p-type thermoelectric material. Thermoelectric properties of the ceramics would be improved by either orientation of grains or introduction of pores. In this study, we fabricated textured Ca3Co4O9 ceramics with controlled density by a reactive-templated grain growth method combined with a hot-forging technique. A powder precursor obtained by mixing β-Co(OH)2 as a template and CaCO3 as a matrix was uniaxially pressed into pellets and sintered under hot-forging pressures up to 5.0 MPa. The relative density of the resulting ceramics was varied between 41.0 and 83.8 % while all the ceramics showed excellent c-axis orientation. The in-plane electrical conductivity of our ceramics could be kept relatively higher than that ever reported previously due to the orientation. Because Seebeck coefficient did not depend on the relative density, the higher electrical conductivity of our ceramics led directly to improved thermoelectric power factors between 67.0 and 409 μW·m−1 K−2. |
| Databáze: | OpenAIRE |
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