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http://hdl.handle.net/10773/19878
Título: | Structure and transport properties of La0.5Sr0.5 (-) xCaxFeO3 (-) (delta) |
Autor: | Chesnokov, K. Yu. Markov, A. A. Patrakeev, M. V. Leonidov, I. A. Murzakaev, A. M. Leonidova, O. N. Shalaeva, E. V. Kharton, V. V. Kozhevnikov, V. L. |
Palavras-chave: | HIGH-TEMPERATURE TRANSPORT MIXED CONDUCTIVITY OXYGEN NONSTOICHIOMETRY MOSSBAUER-SPECTRA ION-TRANSPORT LA1-XSRXFEO3-DELTA MEMBRANES FERRITES EXPANSION STABILITY |
Data: | 2014 |
Editora: | ELSEVIER SCIENCE BV |
Resumo: | Effects of calcium doping on the structure, dimensional stability, and mixed oxygen-ion and electron conductivity of perovskite-like La0.5Sr0.5 - xCaxFeO3 - delta(x = 0-0.3) were studied in light of potential membrane applications. The incorporation of relatively small Ca2+ cations into the lanthanum-strontium ferrite lattice decreases unit cell volume, oxygen nonstoichiometry variations and chemical contribution to the thermal expansion in air. These changes correlate with rising tendency to local oxygen-vacancy ordering and the formation of nano-sized domains with the brownmillerite and LaCa2Fe3O8-type lattices, as revealed by electron diffraction. The resultant vacancy trapping, changing domain structure and enlargement of the interfacial boundary area lead to non-linear relationships between the partial ion conductivity and cation composition, while the apparent activation energy for ion transport at temperatures below 900 degrees C remains almost constant, 0.6-0.7 eV. The n-type electron contribution to the total conductivity, measured in the oxygen pressure range 10(-20)-0.5 atm at 700-950 degrees C, is also essentially independent of the calcium concentration. (C) 2013 Elsevier B.V. All rights reserved. |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/19878 |
DOI: | 10.1016/j.ssi.2013.11.050 |
ISSN: | 0167-2738 |
Versão do Editor: | 10.1016/j.ssi.2013.11.050 |
Aparece nas coleções: | CICECO - Artigos |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
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Structure and transport properties of La0.5Sr 0.5 - XCaxFeO3 - δ_10.1016j.ssi.2013.11.050.pdf | 793.39 kB | Adobe PDF |
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