From nanosized precursors to high performance ceramics: The case of Bi2Ca2Co1.7Ox

•Bi2Ca2Co1.7Ox ceramics have been prepared by different routes.•Nanosized precursors lead to improved homogeneity and density.•Nanoprecursors improve Seebeck coefficient and electrical conductivity.•ZT is drastically improved when compared with sintered materials. Bi2Ca2Co1.7Ox thermoelectric cerami...

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Bibliographic Details
Published inMaterials letters Vol. 191; pp. 14 - 16
Main Authors Madre, M.A., Rasekh, Sh, Touati, K., Salvador, C., Depriester, M., Torres, M.A., Bosque, P., Diez, J.C., Sotelo, A.
Format Journal Article
LanguageEnglish
Published Elsevier B.V 15.03.2017
Elsevier
Subjects
Chemical Sciences
Electrical properties
Electroceramics
Microstructure
Physics
Sintering
Electrical properties
Microstructure
Sintering
Electroceramics
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Summary:•Bi2Ca2Co1.7Ox ceramics have been prepared by different routes.•Nanosized precursors lead to improved homogeneity and density.•Nanoprecursors improve Seebeck coefficient and electrical conductivity.•ZT is drastically improved when compared with sintered materials. Bi2Ca2Co1.7Ox thermoelectric ceramics were prepared by four different synthesis routes: coprecipitation with ammonium carbonate or oxalic acid, attrition milling, and solid state (as reference). Microstructure showed that coprecipitation and attrition milling produced sintered materials with less porosity and smaller particle sizes than the solid state ones. Thermoelectric properties reflect the microstructure, leading to materials with lower electrical resistivity and higher Seebeck coefficient, when compared with the solid state ones. In spite of an increase in thermal conductivity in these samples due to their lower porosity, the maximum estimated Figure-of-Merit is higher than in sintered materials.
ISSN:0167-577X
1873-4979
DOI:10.1016/j.matlet.2017.01.031