• Treffer 4 von 28
Zurück zur Trefferliste

Pressure-assisted sintering of Ca3Co4O9 multilayers for thermoelectric applications

  • The development of competitive thermoelectric generators using oxide ceramics and multilayer technology requires the investigation of suitable sintering procedures. The sintering of Ca3Co4O9, which is the most promising p-type oxide regarding its figure of merit, is a special challenge, as the material starts to decompose at 926 °C. Pressure-assisted sintering (PAS), as known from large-scale production of low temperature co-fired ceramics, was used to sinter multilayers of Ca3Co4O9 green tape at 900 °C with different pressures and dwell times. In-situ shrinkage measurements, microstructural investigations and electric measurements were performed. Relative density increases from 57.4 % after free sintering for 24 h to 93.7 % after 2 h of PAS with 10 MPa axial load. The combination of tape casting and PAS induces a pronounced alignment of the anisotropic grains. In comparison to freely sintered multilayers, the electrical conductivity in the casting direction is thereby stronglyThe development of competitive thermoelectric generators using oxide ceramics and multilayer technology requires the investigation of suitable sintering procedures. The sintering of Ca3Co4O9, which is the most promising p-type oxide regarding its figure of merit, is a special challenge, as the material starts to decompose at 926 °C. Pressure-assisted sintering (PAS), as known from large-scale production of low temperature co-fired ceramics, was used to sinter multilayers of Ca3Co4O9 green tape at 900 °C with different pressures and dwell times. In-situ shrinkage measurements, microstructural investigations and electric measurements were performed. Relative density increases from 57.4 % after free sintering for 24 h to 93.7 % after 2 h of PAS with 10 MPa axial load. The combination of tape casting and PAS induces a pronounced alignment of the anisotropic grains. In comparison to freely sintered multilayers, the electrical conductivity in the casting direction is thereby strongly increased by a factor of 5. With respect to dry-pressed bars, the improvement amounts to a factor of 15. This study shows that PAS is a proper technique to produce dense Ca3Co4O9 panels with good thermoelectric properties similar to hot-pressed tablets, even in large-scale production.zeige mehrzeige weniger

Volltext Dateien herunterladen

  • Mieller_Sintering2017.pdf
    eng

Metadaten exportieren

Weitere Dienste

Teilen auf Twitter Suche bei Google Scholar
Metadaten
Autoren/innen:Bjoern Mieller
Koautoren/innen:Sophie Bresch, Torsten Rabe
Dokumenttyp:Vortrag
Veröffentlichungsform:Präsentation
Sprache:Englisch
Jahr der Erstveröffentlichung:2017
Organisationseinheit der BAM:5 Werkstofftechnik
5 Werkstofftechnik / 5.5 Technische Keramik
DDC-Klassifikation:Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Angewandte Physik
Freie Schlagwörter:Calcium cobaltite; Multilayer; Sintering; Thermoelectric oxide
Themenfelder/Aktivitätsfelder der BAM:Energie
Veranstaltung:International Conference on Sintering 2017
Veranstaltungsort:San Diego, USA
Beginndatum der Veranstaltung:12.11.2017
Enddatum der Veranstaltung:16.11.2017
Verfügbarkeit des Volltexts:Volltext-PDF im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:20.11.2017
Referierte Publikation:Nein