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Influence of pressure and dwell time on pressure‐assisted sintering of calcium cobaltite
- Calcium cobaltite Ca3Co4O9, abbreviated Co349, is a promising thermoelectric material for high‐temperature applications in air. Its anisotropic properties can be assigned to polycrystalline parts by texturing. Tape casting and pressure‐assisted sintering (PAS) are a possible future way for a cost‐effective mass‐production of thermoelectric generators. This study examines the influence of pressure and dwell time during PAS at 900°C of tape‐cast Co349 on texture and thermoelectric properties. Tape casting aligns lentoid Co349. PAS results in a textured Co349 microstructure with the thermoelectrically favorable ab‐direction perpendicular to the pressing direction. By pressure variation during sintering, the microstructure of Co349 can be tailored either toward a maximum figure of merit as required for energy harvesting or toward a maximum power factor as required for energy harvesting. Moderate pressure of 2.5 MPa results in 25% porosity and a textured microstructure with a figure ofCalcium cobaltite Ca3Co4O9, abbreviated Co349, is a promising thermoelectric material for high‐temperature applications in air. Its anisotropic properties can be assigned to polycrystalline parts by texturing. Tape casting and pressure‐assisted sintering (PAS) are a possible future way for a cost‐effective mass‐production of thermoelectric generators. This study examines the influence of pressure and dwell time during PAS at 900°C of tape‐cast Co349 on texture and thermoelectric properties. Tape casting aligns lentoid Co349. PAS results in a textured Co349 microstructure with the thermoelectrically favorable ab‐direction perpendicular to the pressing direction. By pressure variation during sintering, the microstructure of Co349 can be tailored either toward a maximum figure of merit as required for energy harvesting or toward a maximum power factor as required for energy harvesting. Moderate pressure of 2.5 MPa results in 25% porosity and a textured microstructure with a figure of merit of 0.13 at 700°C, two times higher than the dry‐pressed, pressureless‐sintered reference. A pressure of 7.5 MPa leads to 94% density and a high power factor of 326 µW/mK2 at 800°C, which is 11 times higher than the dry‐pressed reference (30 MPa) from the same powder.…
Autor*innen: | Sophie BreschORCiD, Björn MiellerORCiD, D. Schönauer-Kamin, R. Moos, T. Reimann, F. Giovannelli, Torsten Rabe |
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Dokumenttyp: | Zeitschriftenartikel |
Veröffentlichungsform: | Verlagsliteratur |
Sprache: | Englisch |
Titel des übergeordneten Werkes (Englisch): | Journal of the American Ceramic Society |
Jahr der Erstveröffentlichung: | 2020 |
Organisationseinheit der BAM: | 5 Werkstofftechnik |
5 Werkstofftechnik / 5.4 Multimateriale Fertigungsprozesse | |
Veröffentlichende Institution: | Bundesanstalt für Materialforschung und -prüfung (BAM) |
Verlag: | Wiley Periodicals LLC |
Jahrgang/Band: | 104 |
Ausgabe/Heft: | 2 |
Erste Seite: | 917 |
Letzte Seite: | 927 |
DDC-Klassifikation: | Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten |
Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Angewandte Physik | |
Freie Schlagwörter: | Hot pressing; Texture; Thermoelectric properties |
Themenfelder/Aktivitätsfelder der BAM: | Energie |
Material | |
DOI: | https://doi.org/10.1111/jace.17541 |
URN: | urn:nbn:de:kobv:b43-515973 |
ISSN: | 0002-7820 |
Verfügbarkeit des Dokuments: | Datei für die Öffentlichkeit verfügbar ("Open Access") |
Lizenz (Deutsch): | Creative Commons - CC BY - Namensnennung 4.0 International |
Datum der Freischaltung: | 19.11.2020 |
Referierte Publikation: | Ja |
Datum der Eintragung als referierte Publikation: | 19.11.2020 |
Schriftenreihen ohne Nummerierung: | Wissenschaftliche Artikel der BAM |