Evaluation of pressure and temperature effect on the structure and properties of Ca2.93Sr0.07Co4O9 ceramic materials

Torres M.A. (Universidad de Zaragoza) ; Madre M.A. (Universidad de Zaragoza) ; Dura O.J. ; García G. ; Marinel S. ; Martinez-Filgueira P. ; Sotelo A.

Resumen: In this work, the effect of hot-pressing conditions on the performances of Sr-doped Ca3Co4O9 materials has been investigated. The samples were prepared from attrition milled precursors, which reduced the processing time. Samples were hot-pressed at temperatures (T) between 800 and 900 °C and pressures (P) from 51 to 71 MPa. The out-of-plane X-ray diffraction (XRD) showed that all samples are formed by the thermoelectric phase, with a good grain orientation which is improved with T, and P, as demonstrated by their Lotgering factor. The observations through Scanning Electron Microscopy (SEM) have revealed that grain sizes and orientation are enhanced with T, and P, as well as density through Archimedes''s method. All these trends are reflected in the flexural strength and microhardness. The electrical resistivity is lower when the T, or P, is increased, reaching 6.4 mO cm for samples processed at 900 °C and 71 MPa, which is about the best reported values in the literature. On the other hand, contrarily to the expected results, they also showed the highest S values, 182 µV/K, which are similar to the best reported values for highly dense textured materials. Thermal conductivity values do not follow a regular evolution with the hot-pressing conditions, probably due to internal stresses, reaching the lowest values at 800 °C in samples processed at 800 °C and 51 MPa (1.51 W/(K*m)) or 900 °C and 61 MPa (1.53 W/(K*m)). Consequently, the highest ZT values have been determined in samples processed at 900 °C and 61 MPa (0.35) which is higher than the best reported values in literature for bulk textured samples, to the best of our knowledge. © 2021 The Authors

Idioma: Inglés

DOI: 10.1016/j.ceramint.2021.11.321

Año: 2022

Publicado en: Ceramics International 48, 6 (2022), 7730-7747
ISSN: 0272-8842

Factor impacto JCR: 5.2 (2022)

Categ. JCR: MATERIALS SCIENCE, CERAMICS rank: 3 / 29 = 0.103 (2022) - Q1 - T1

Factor impacto CITESCORE: 8.8 - Chemical Engineering (Q1) - Materials Science (Q1)

Factor impacto SCIMAGO: 0.918 - Ceramics and Composites (Q1) - Electronic, Optical and Magnetic Materials (Q1) - Surfaces, Coatings and Films (Q1) - Materials Chemistry (Q1) - Process Chemistry and Technology (Q2)

Financiación: info:eu-repo/grantAgreement/ES/DGA/T54-20R
Financiación: info:eu-repo/grantAgreement/ES/MINECO-FEDER/MAT2017-82183-C3-1-R

Tipo y forma: Article (Published version)

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