Mixed conductivity of garnet phases based on gadolinium ferrite
authors Shaula, AL; Kharton, VV; Marques, FMB
nationality International
journal JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
author keywords ferrites; garnets; ionic conductivity; membranes; thermal expansion
keywords YTTRIUM-ALUMINUM; SOLID-SOLUTIONS; TRANSPORT
abstract Incorporation of Pr and Ca into the garnet lattice of Gd3Fe5O12 (+/- delta) was found to increase the electronic conductivity, and to decrease the thermal expansion coefficients and oxygen ion transference numbers. The ionic conductivity of Gd2.2Pr0.8Fe5O12+/-delta ceramics is similar to that of undoped gadolinium ferrite, whilst Gd2.5Ca0.5Fe5O12-delta exhibits slightly higher ionic transport, suggesting an enhanced vacancy contribution. The activation energies for ionic conduction in Gd3Fe5O12-based materials vary in the narrow range 211-224 kJ/mol. Due to a significantly lower activation energy for the total conductivity (24-81 kJ/mol), the oxygen ion transference numbers in air increase with temperature, from 4 x 10(-5) - 5 x 10(-3). Steady-state oxygen permeation fluxes through dense garnet membranes are limited by bulk ambipolar conductivity. The thermal expansion coefficients of the ferrite ceramics (100-1000 degreesC were found linear and in the range 10.36-10.86 x 10(-6) K-1. (C) 2003 Elsevier Ltd. All rights reserved.
publisher ELSEVIER SCI LTD
issn 0955-2219
year published 2004
volume 24
issue 6
beginning page 1309
ending page 1312
digital object identifier (doi) 10.1016/S0955-2219(03)00505-3
web of science category Materials Science, Ceramics
subject category Materials Science
unique article identifier WOS:000189247800083
  ciceco authors
  impact metrics
journal analysis (jcr 2019):
journal impact factor 4.495
5 year journal impact factor 4.283
category normalized journal impact factor percentile 98.214
dimensions (citation analysis):
altmetrics (social interaction):



 


Apoio

1suponsers_list_ciceco.jpg