Influence of pressure and dwell time on pressure-assisted sintering of calcium cobaltite

Title data

Bresch, Sophie ; Mieller, Bjoern ; Schönauer-Kamin, Daniela ; Moos, Ralf ; Reimann, Timmy ; Giovannelli, Fabien ; Rabe, Torsten:
Influence of pressure and dwell time on pressure-assisted sintering of calcium cobaltite.
In: Journal of the American Ceramic Society. Vol. 104 (2021) Issue 2 . - pp. 917-927.
ISSN 1551-2916
DOI: https://doi.org/10.1111/jace.17541

Official URL:

Abstract in another language

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 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.

Further data

Item Type:	Article in a journal
Refereed:	Yes
Institutions of the University:	Faculties > Faculty of Engineering Science Faculties > Faculty of Engineering Science > Chair Functional Materials > Chair Functional Materials - Univ.-Prof. Dr.-Ing. Ralf Moos Profile Fields > Advanced Fields > Advanced Materials Research Institutions > Central research institutes > Bayreuth Center for Material Science and Engineering - BayMAT Faculties Faculties > Faculty of Engineering Science > Chair Functional Materials Profile Fields Profile Fields > Advanced Fields Research Institutions Research Institutions > Central research institutes
Result of work at the UBT:	Yes
DDC Subjects:	600 Technology, medicine, applied sciences > 620 Engineering
Date Deposited:	14 Dec 2020 11:54
Last Modified:	16 May 2024 07:39
URI:	https://eref.uni-bayreuth.de/id/eprint/61027