Oxygen permeability and thermal expansion of ferrite-based mixed conducting ceramics
authors Kharton, VV; Yaremchenko, AA; Shaula, AL; Viskup, AP; Marques, FMB; Frade, JR; Naumovich, EN; Casanova, JR; Marozau, IP
editors Fisher, DJ
nationality International
journal DEFECTS AND DIFFUSION IN CERAMICS - AN ANNUAL RETROSPECTIVE VI
author keywords ceramic membranes; composites; ferrites; garnets; ionic transport; mixed conductors; oxygen permeability; perovskites; thermal expansion
keywords PEROVSKITE-TYPE OXIDES; IONIC TRANSPORT; PERMEATION PROPERTIES; COMBUSTION SYNTHESIS; SYNGAS PRODUCTION; HIGH-TEMPERATURES; DEFECT STRUCTURE; PHASE; SEPARATION; STABILITY
abstract In order to evaluate promising directions in the development of mixed-conducting membrane materials for oxygen separation and partial oxidation of natural gas, a series of ferritebased ceramics were studied, including La1-xSrxFe1-yGayO3-8 (x = 0.5 - 0.8; y = 0 - 0.4), La1-xSrxFe1-yAlyO3-delta (x = 0.7 - 1.0; y = 0 - 0.5), La0.3Sr0.7Fe0.7-XAl0.3CrXO3-delta (x = 0.1 - 0.2), (Sr2Fe3)(1-X)(SrCo)(X)O-Z (x = 0 - 0.8), CaFe0.5Al0.5O2.5+delta and Ln(3-x)Ca(X)Fe(5)O(12-delta) (Ln = Gd, Y; x = 0 - 0.5). The maximum oxygen permeation is observed for perovskite-type solid solutions with high oxygen deficiency, which exhibit, however, excessive thermal and chemically induced expansion. As for cobaltite- and gallate-based mixed conductors, the increase in ionic transport is accompanied with increasing limiting role of the surface exchange processes. The stability of perovskite-related ferrites in reducing atmospheres, which is comparable to that of LaFeO3-delta and iron oxide, may be moderately increased or decreased by donor- or acceptor-type doping, respectively. In addition, the substitution of iron with cations having a more stable oxidation state, such as Ga3+, Al3+ or Cr3+/4+, partly prevents the lattice expansion induced by oxygen nonstoichiometry variations, although the solubility of these dopants in the ferrite lattice is limited.
publisher TRANS TECH PUBLICATIONS LTD
issn 1012-0386
year published 2004
volume 226-228
beginning page 141
ending page 159
web of science category Materials Science, Multidisciplinary; Physics, Condensed Matter
subject category Materials Science; Physics
unique article identifier WOS:000224960300010

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