Effects of sintering additives on the mixed transport properties of ceria-based materials under reducing conditions
authors Perez-Coll, D; Nunez, P; Marrero-Lopez, D; Abrantes, JCC; Frade, JR
nationality International
journal JOURNAL OF SOLID STATE ELECTROCHEMISTRY
author keywords cobalt-doped ceria; electronic conductivity; ion blocking; n-type conductivity; sintering additives
keywords GD-DOPED CERIA; ELECTRONIC CONDUCTIVITY; IONIC-CONDUCTIVITY; DC TECHNIQUES; CERAMICS; ELECTROLYTES; CONDUCTORS
abstract Commercial Ce0.8Gd0.2O2-delta nanopowders and alternative precursors synthesized by a freeze-drying method were used to obtain samples with and without Co addition as a sintering agent. Two percent Co-doped samples were sintered at 1150degreesC and 1500degreesC and undoped samples were sintered at 1500degreesC or 1600degreesC to obtain samples with relative densities in the range 92-94%. The total conductivity and the relative roles of bulk and grain boundary conductivity were studied by impedance spectroscopy. These results demonstrated that additions of Co play a very significant effect on the grain boundary behaviour, which is spoiled when the sintering temperature is excessive. Significant differences in grain boundary behaviour were also found between samples prepared from different precursor powders. The electronic conductivity of these materials was evaluated by an ion-blocking method and revealed that samples containing Co additions as a sintering additive possess somewhat lower n-type conductivity under identical conditions of temperature and oxygen partial pressure. The differences tend to vanish when these Co-doped samples are fired at high temperatures (1500degreesC).
publisher SPRINGER
issn 1432-8488
year published 2004
volume 8
issue 9
beginning page 644
ending page 649
digital object identifier (doi) 10.1007/s10008-004-0505-1
web of science category Electrochemistry
subject category Electrochemistry
unique article identifier WOS:000223022400012
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