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http://hdl.handle.net/10773/19408
Título: | Ionic conductivity of directionally solidified zirconia-mullite eutectics |
Autor: | Carvalho, Ricardo G. Kovalevsky, Andrei V. Lufaso, Michael W. Silva, Rui F. Costa, Florinda M. Figueiredo, Filipe M. |
Palavras-chave: | ELECTRICAL-CONDUCTIVITY STABILIZED ZIRCONIA PHYSICAL-PROPERTIES COMPOSITES MICROSTRUCTURE OXIDE DIFFRACTION FIBERS SINGLE |
Data: | 2014 |
Editora: | ELSEVIER SCIENCE BV |
Resumo: | The properties of directionally solidified eutectic (DSE) zirconia-mullite composites are presented. These materials combine two oxide ion conductors in eutectic microstructures stable over broad temperature (570-1415 degrees C) and PO2 (10(-20) to 10(5) Pa) ranges, which are pertinent for their application as high temperature (>1200 degrees C) solid electrolytes, e.g. in Nernstian sensors. X-ray diffraction and scanning electron microscopy/energy dispersive spectroscopy results reveal a composite structure comprising eutectic crystals of mullite and zirconia, and an intergranular amorphous phase rich in Al-Y-Si-O. The amorphous phase is crystallised upon annealing at 1400 degrees C, and the resulting composites have a composition close to the nominal eutectic consisting of 79 vol.% mullite and 21 vol.% zirconia. The electrical conductivity of these materials is rationalized in terms of percolation, fraction and properties of each phase, attaining values in excess of 0.01 S/cm at 1370 degrees C and displaying Arrhenius behaviour with activation energy of 70 kJ/mol. The broad electrolytic domain of these solid electrolytes is demonstrated by conductivity measurements carried out from 600 degrees C to 1370 degrees C in O2, air, Ar and 10%H-2 + 90%N-2 atmospheres. (C) 2013 Elsevier B.V. All rights reserved. |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/19408 |
DOI: | 10.1016/j.ssi.2013.12.033 |
ISSN: | 0167-2738 |
Versão do Editor: | 10.1016/j.ssi.2013.12.033 |
Aparece nas coleções: | CICECO - Artigos |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
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Ionic conductivity of directionally solidified zirconia-mullite eutectics_10.1016j.ssi.2013.12.033.pdf | 1.17 MB | Adobe PDF |
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