Effects of Fe-additions on sintering and transport properties of Yb2Ti2-yFeyO7-delta
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
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journal analysis (jcr 2017):
journal impact factor 3.794
5 year journal impact factor 3.536
category normalized journal impact factor percentile 98.148
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