authors |
Horovistiz, AL; Fagg, DP; Abrantes, JCC; Frade, JR |
nationality |
International |
journal |
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY |
author keywords |
grain boundaries; electrical conductivity; impedance; ionic conductivity; pyrochlore |
keywords |
FUEL-CELL MATERIALS; IONIC-CONDUCTIVITY; PYROCHLORE; SYSTEM; TEMPERATURE; FLUORITE |
abstract |
Partial substitution of Fe for Ti in Yb2Ti2-yFeyO7-delta has been used to improve the sinterability of these ion conducting pyrochlore-type materials, and to adjust their transport properties. Fe additions displace the maximum shrinkage rate to lower temperatures and allow the preparation of dense materials at lower firing temperatures. Impedance spectroscopy was used to de-convolute the effects of Fe additions on the bulk and grain boundary conductivities. The bulk conductivity was enhanced for relatively low Fe additions (< 5%) and its activation energy was lowered. The grain boundary conductivity was also enhanced. The dependence of total conductivity on oxygen partial pressure shows that this enhancement corresponds to ionic conductivity. The onset of n-type conductivity is displaced to more reducing conditions with Fe addition. (c) 2007 Published by Elsevier Ltd. |
publisher |
ELSEVIER SCI LTD |
issn |
0955-2219 |
year published |
2007 |
volume |
27 |
issue |
13-15 |
beginning page |
4283 |
ending page |
4286 |
digital object identifier (doi) |
10.1016/j.jeurceramsoc.2007.02.133 |
web of science category |
Materials Science, Ceramics |
subject category |
Materials Science |
unique article identifier |
WOS:000248822800151
|