Please use this identifier to cite or link to this item: http://hdl.handle.net/10773/19570
Title: Thermochemical expansion of mixed-conducting (Ba,Sr)Co0.8Fe0.2O3-delta ceramics
Author: Yaremchenko, A. A.
Mikhalev, S. M.
Kravchenko, E. S.
Frade, J. R.
Keywords: PEROVSKITE-TYPE OXIDES
SITU NEUTRON-DIFFRACTION
CHEMICAL EXPANSION
OXYGEN PERMEABILITY
FUEL-CELLS
PHASE-STABILITY
BA0.5SR0.5CO0.8FE0.2O3-DELTA PEROVSKITE
INTERMEDIATE TEMPERATURES
ELECTRICAL-PROPERTIES
EXCHANGE KINETICS
Issue Date: 2014
Publisher: ELSEVIER SCI LTD
Abstract: The thermal and chemical expansion of Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) and SrCo0.8Fe0.2O3-delta (SCF) mixed ionic-electronic conductors were studied in combination with oxygen nonstoichiometry (delta) at 298-1223 K and p(O-2) = 10(-4) to 1.00 atm. In order to minimize the effects of phase separation or oxygen-vacancy ordering processes, the data were collected in dynamic cooling mode using dense ceramic samples. The procedure was justified by a very fast equilibration at given p(O-2) in high-temperature range demonstrated for ceramics samples with different specific surface area. The difference in nonstoichiometry of BSCF and SCF at temperatures >= 973 K was found to be <= 0.03 oxygen atoms per formula unit. BSCF demonstrates favorably smaller chemical expansion compared to SCF and many other mixed conductors, originating from smaller delta variations and larger unit cell less sensitive to temperature and nonstoichiometry changes. Excessive thermochemical expansion impedes however the use of BSCF in single-phase fuel cell cathodes and planar mixed-conducting membranes. (C) 2013 Elsevier Ltd. All rights reserved.
Peer review: yes
URI: http://hdl.handle.net/10773/19570
DOI: 10.1016/j.jeurceramsoc.2013.09.012
ISSN: 0955-2219
Publisher Version: 10.1016/j.jeurceramsoc.2013.09.012
Appears in Collections:CICECO - Artigos



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