Effect of simultaneous K, and Yb substitution for Ca on the microstructural and thermoelectric characteristics of CaMnO3 ceramics

Sotelo, A. (Universidad de Zaragoza) ; Depriester, M. ; Torres, M.A. (Universidad de Zaragoza) ; Sahraoui, A.H. ; Madre, M.A. (Universidad de Zaragoza) ; Diez, J.C. (Universidad de Zaragoza)

Resumen: CaMnO3-based materials are very attractive among n-type thermoelectric oxides for high-temperature applications when they are appropriately doped. The main drawback of these materials is the cost associated to the necessary rare earth cations. This work aims decreasing the amount of these materials through a partial substitution of Ca2+ by an equimolar mixture of K+ and Yb3+, Ca1-x(K0.5Yb0.5)xMnO3, with x = 0.05, 0.10, 0.15, and 0.20. XRD studies have confirmed that the thermoelectric phase is the major one in all samples. Microstructure has shown the formation of large crystals, and an increasing porosity when the substitution is raised. This evolution has been confirmed through density measurements. Electrical resistivity has been drastically decreased for the 0.10 substituted samples, compared with the 0.05 ones, slightly increasing for higher substitution. On the other hand, absolute Seebeck coefficient and thermal conductivity are lower when the substitution is raised. The best ZT values have been achieved for the 0.10 substituted samples, which are around the typical reported in the literature for higher doping level. These results clearly point out to a decrease of the necessary rare earth dopant content to achieve similar performances in CaMnO3 ceramics, which is of the main economic significance for their industrial production.

Idioma: Inglés

DOI: 10.1016/j.ceramint.2018.04.071

Año: 2018

Publicado en: Ceramics International 44, 11 (2018), 12697-12701
ISSN: 0272-8842

Factor impacto JCR: 3.45 (2018)

Categ. JCR: MATERIALS SCIENCE, CERAMICS rank: 2 / 28 = 0.071 (2018) - Q1 - T1

Factor impacto SCIMAGO: 0.888 - Electronic, Optical and Magnetic Materials (Q1) - Ceramics and Composites (Q1) - Surfaces, Coatings and Films (Q1) - Process Chemistry and Technology (Q1) - Materials Chemistry (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA-FEDER/T12
Financiación: info:eu-repo/grantAgreement/ES/DGA-FEDER/T87
Financiación: info:eu-repo/grantAgreement/ES/MINECO-FEDER/MAT2017-82183-C3-1-R
Financiación: info:eu-repo/grantAgreement/ES/UZ/UZ2017-TEC-03

Tipo y forma: Article (PostPrint)

Área (Departamento): Área Expresión Gráfica en Ing. (Dpto. Ingeniería Diseño Fabri.)
Área (Departamento): Área Cienc.Mater. Ingen.Metal. (Dpto. Ciencia Tecnol.Mater.Fl.)