Publicação
Nonstoichiometry, thermal expansion and oxygen permeability of SmBaCo2-xCuxO6-delta
| Resumo: | Phase relationship analysis in the pseudobinary SmBaCo2 - xCuxO6 - delta system at 1000-1100 degrees C in air revealed the existence of solid solutions with the layered perovskite and 123-type structures, formed within the ranges of 0 <= x <1.2 and 1.5 <= x <= 2.0, respectively. The substitution of Cu2+ for Co3+/4+ was found to induce phase transition from orthorhombic (space group Pmmm) into tetragonal (P4/mmm) polymorph at x > 0.1, and to increase oxygen deficiency studied by thermogravimetry and iodometric titration. The electrical conductivity and thermal expansion of Cu-substituted cobaltites decrease on doping, while the steady-state Oxygen permeability exhibits an opposite trend, in correlation with the oxygen content variations. The average thermal expansion coefficient of SmBaCo1.4Cu0.6O6 - delta ceramics, where the level of ionic transport is comparable to that in most permeable cobaltite-based mixed conductors, is 16.9 x 10(-6) K-1 at 25-1000 degrees C in air. At the same time, copper additions increase chemical reactivity of the materials with doped ceria electrolytes. (C) 2014 Elsevier B.V. All rights reserved. |
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| Autores principais: | Volkova, N. E. |
| Outros Autores: | Kolotygin, V. A.; Gavrilova, L. Ya.; Kharton, V. V.; Cherepanov, V. A. |
| Assunto: | OXIDE FUEL-CELLS CRYSTAL-STRUCTURE ELECTROCHEMICAL PROPERTIES CERAMIC MICROSTRUCTURE TRANSPORT-PROPERTIES CATHODE MATERIAL IONIC TRANSPORT MEMBRANES TEMPERATURE LNBACO(2)O(5+DELTA) |
| Ano: | 2014 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso restrito |
| Instituição associada: | Universidade de Aveiro |
| Idioma: | inglês |
| Origem: | RIA - Repositório Institucional da Universidade de Aveiro |
| Resumo: | Phase relationship analysis in the pseudobinary SmBaCo2 - xCuxO6 - delta system at 1000-1100 degrees C in air revealed the existence of solid solutions with the layered perovskite and 123-type structures, formed within the ranges of 0 <= x <1.2 and 1.5 <= x <= 2.0, respectively. The substitution of Cu2+ for Co3+/4+ was found to induce phase transition from orthorhombic (space group Pmmm) into tetragonal (P4/mmm) polymorph at x > 0.1, and to increase oxygen deficiency studied by thermogravimetry and iodometric titration. The electrical conductivity and thermal expansion of Cu-substituted cobaltites decrease on doping, while the steady-state Oxygen permeability exhibits an opposite trend, in correlation with the oxygen content variations. The average thermal expansion coefficient of SmBaCo1.4Cu0.6O6 - delta ceramics, where the level of ionic transport is comparable to that in most permeable cobaltite-based mixed conductors, is 16.9 x 10(-6) K-1 at 25-1000 degrees C in air. At the same time, copper additions increase chemical reactivity of the materials with doped ceria electrolytes. (C) 2014 Elsevier B.V. All rights reserved. |
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