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Author Sotelo, A. ♦ Rasekh, Sh. ♦ Torres, M. A. ♦ Bosque, P. ♦ Madre, M. A. ♦ Diez, J. C.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY ♦ CALCIUM CARBONATES ♦ CERAMICS ♦ COPRECIPITATION ♦ DENSITY ♦ ELECTRICAL PROPERTIES ♦ GRAIN SIZE ♦ HEAT TREATMENTS ♦ MILLING ♦ NANOSTRUCTURES ♦ OXALIC ACID ♦ PARTICLE SIZE ♦ POWER FACTOR ♦ SOLIDS ♦ SYNTHESIS ♦ TEXTURE ♦ THERMOELECTRIC MATERIALS
Abstract Three different synthesis methods producing nanometric grain sizes, coprecipitation with ammonium carbonate, oxalic acid, and by attrition milling have been studied to produce Ca{sub 3}Co{sub 4}O{sub 9} ceramics and compared with the classical solid state route. These three processes have produced high reactive precursors and all the organic material and CaCO{sub 3}·have been decomposed in a single thermal treatment. Coprecipitation leads to pure Ca{sub 3}Co{sub 4}O{sub 9} phase, while attrition milling and classical solid state produce small amounts of Ca{sub 3}Co{sub 2}O{sub 6} secondary phase. Power factor values are similar for all three samples, being slightly lower for the ones produced by attrition milling. These values are much higher than the obtained in samples prepared by the classical solid state method, used as reference. The maximum power factor values determined at 800 °C (∼0.43 mW/K{sup 2} m) are slightly higher than the best reported values obtained in textured ones which also show much higher density values. - Graphical abstract: Impressive raise of PF in Ca{sub 3}Co{sub 4}O{sub 9} thermoelectric materials obtained from nanometric grains. - Highlights: • Ca{sub 3}Co{sub 4}O{sub 9} has been produced by four different methods. • Precursors particle sizes influences on the final performances. • Coprecipitation methods produce single Ca{sub 3}Co{sub 4}O{sub 9} phase. • Power factor reaches values comparable to high density textured materials.
ISSN 00224596
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-01-15
Publisher Place United States
Journal Journal of Solid State Chemistry
Volume Number 221


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