Grain size effects on oxygen permeation in submicrometric CaTi0.8Fe0.2O3-δ ceramics obtained by mechanical activation

Ceramic samples of CaTi0*8Fe0*2O3--delta were obtained from mechanically activated mixtures of TiO2, Fe2O3 and CaCO3 sintered at 1150 deg C for 2h. The ceramics are dense with submicrometric grains with sizes in the order of 100--200nm and 400--600nm. X--ray diffraction analysis revealed a single pe...

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Veröffentlicht in:Journal of the European Ceramic Society 2005, Vol.25 (12), p.2613-2616
Hauptverfasser: SHAULA, A. L, FUENTES, R. O, FIGUEIREDO, F. M, KHARTON, V. V, MARQUES, F. M. B, FRADE, J. R
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Sprache:eng
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Zusammenfassung:Ceramic samples of CaTi0*8Fe0*2O3--delta were obtained from mechanically activated mixtures of TiO2, Fe2O3 and CaCO3 sintered at 1150 deg C for 2h. The ceramics are dense with submicrometric grains with sizes in the order of 100--200nm and 400--600nm. X--ray diffraction analysis revealed a single perovskite phase structure indicating a high level of homogeneity, which was confirmed by transmission electron microscopy. The oxygen permeability through these samples, measured in the range 700--950 deg C, is about 50% lower than for ceramics with considerably larger grains, close to 10mum. The permeability increases linearly with the increase of the grain size in the range from ~200nm to ~10mum. Observations by results suggest that the grain boundaries have a negative impact on the high temperature ionic transport properties of CaTi0*8Fe0*2O3--delta ceramics.
ISSN:0955-2219
1873-619X
DOI:10.1016/j.jeurceramsoc.2005.03.112