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Entwicklung oxidkeramischer Werkstoffe und Folien für thermoelektrische Multilayergeneratoren

  • Calcium cobaltite is a promising oxide thermoelectric materials for applications between 600 °C and 900 °C in air to convert waste heat directly into electrical power. The solid-state reaction, well known for large scale powder synthesis of functional materials, is used for the production of thermoelectric oxides. As a high temperature process, the powder synthesis consumes a lot of energy. In different studies, different synthesis conditions were used for the preparation of calcium cobaltite. To the author’s knowledge, a systematic study of the synthesis conditions of calcium cobaltite and calcium manganate has not yet been published. Therefore, the synthesis conditions for calcium cobaltite (temperature, dwell time, and particle size of raw materials) were studied with a statistical design of experiments (2³) and investigated regarding phase composition (XRD), densification, and thermoelectric properties. This study showed that a higher energy input (elevated temperatures, longerCalcium cobaltite is a promising oxide thermoelectric materials for applications between 600 °C and 900 °C in air to convert waste heat directly into electrical power. The solid-state reaction, well known for large scale powder synthesis of functional materials, is used for the production of thermoelectric oxides. As a high temperature process, the powder synthesis consumes a lot of energy. In different studies, different synthesis conditions were used for the preparation of calcium cobaltite. To the author’s knowledge, a systematic study of the synthesis conditions of calcium cobaltite and calcium manganate has not yet been published. Therefore, the synthesis conditions for calcium cobaltite (temperature, dwell time, and particle size of raw materials) were studied with a statistical design of experiments (2³) and investigated regarding phase composition (XRD), densification, and thermoelectric properties. This study showed that a higher energy input (elevated temperatures, longer dwell times, or repeated calcinations) during powder synthesis does not improve but deteriorate the thermoelectric properties of calcium cobaltite. The same correlation was determined for the shrinkage. As a higher energy input during powder synthesis leads to a larger grain size and therefore to a reduced sinter activity the shrinkage at a given sinter profile is minimize as well as the thermoelectric properties. These results can be used to minimize the energy demand for the powder synthesis of oxide thermoelectric materials. In addition an increase of power factor by factor 10 can be achieved by applying pressure assisted sintering.zeige mehrzeige weniger

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Metadaten
Autoren/innen:Sophie Bresch
Dokumenttyp:Vortrag
Veröffentlichungsform:Präsentation
Sprache:Deutsch
Jahr der Erstveröffentlichung:2016
Organisationseinheit der BAM:5 Werkstofftechnik
5 Werkstofftechnik / 5.5 Technische Keramik
DDC-Klassifikation:Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten
Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Angewandte Physik
Freie Schlagwörter:Calcium cobaltite; Solid-state-reaction; Thermoelectrics
Themenfelder/Aktivitätsfelder der BAM:Energie
Material
Material / Materialien und Stoffe
Veranstaltung:Funktionsmaterialien - Lehrstuhlseminar
Veranstaltungsort:Bayreuth, Germany
Beginndatum der Veranstaltung:18.11.2016
Verfügbarkeit des Dokuments:Datei im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:22.11.2016
Referierte Publikation:Nein