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Title: Oxygen nonstoichiometry and transport properties of strontium substituted lanthanum ferrite

Abstract

This study presents an investigation of the properties of (La{sub 0.6}Sr{sub 0.4}){sub 0.99}FeO{sub 3-{delta}} (LSF40) covering thermomechanical properties, oxygen nonstoichiometry and electronic and ionic conductivity. Finally, oxygen permeation experiments have been carried out and the oxygen flux has been determined as a function of temperature and driving force. The electrical conductivity was measured using a 4 probe method. It is shown that the electrical conductivity is a function of the charge carrier concentration only. The electron hole mobility is found to decrease with increasing charge carrier concentration in agreement with recent literature. Values of the chemical diffusion coefficient, D{sub Chem}, and the surface exchange coefficient, k{sub Ex}, have been determined using electrical conductivity relaxation. At 800 deg. CD{sub Chem} is determined to be 6.2x10{sup -6}cm{sup 2}s{sup -1} with an activation energy of 137kJmol{sup -1}. The surface exchange coefficient is found to decrease with decreasing oxygen partial pressure. Oxygen permeation experiments were carried out. The flux through a membrane placed between air and wet hydrogen/nitrogen was J{sub O{sub 2}}{approx}1.8x10{sup -6}molcm{sup -2}s{sup -1} (corresponding to an equivalent electrical current density of 670mAcm{sup -2}). The oxygen permeation measurements are successfully interpreted based on the oxygen nonstoichiometry data and the determined transport parameters.

Authors:
 [1];  [2];  [2]
  1. Fuel Cells and Solid State Chemistry Department, Riso National Laboratory, Frederiksborgvej 399, DK-4000 Roskilde (Denmark), E-mail: martin.soegaard@risoe.dk
  2. Fuel Cells and Solid State Chemistry Department, Riso National Laboratory, Frederiksborgvej 399, DK-4000 Roskilde (Denmark)
Publication Date:
OSTI Identifier:
21015800
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 180; Journal Issue: 4; Other Information: DOI: 10.1016/j.jssc.2007.02.012; PII: S0022-4596(07)00086-2; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ACTIVATION ENERGY; CHARGE CARRIERS; DIFFUSION; ELECTRIC CURRENTS; FERRITES; IONIC CONDUCTIVITY; LANTHANUM COMPOUNDS; OXYGEN; OXYGEN IONS; PARTIAL PRESSURE; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 1000-4000 K; THERMAL EXPANSION

Citation Formats

Sogaard, Martin, Vang Hendriksen, Peter, and Mogensen, Mogens. Oxygen nonstoichiometry and transport properties of strontium substituted lanthanum ferrite. United States: N. p., 2007. Web. doi:10.1016/j.jssc.2007.02.012.
Sogaard, Martin, Vang Hendriksen, Peter, & Mogensen, Mogens. Oxygen nonstoichiometry and transport properties of strontium substituted lanthanum ferrite. United States. doi:10.1016/j.jssc.2007.02.012.
Sogaard, Martin, Vang Hendriksen, Peter, and Mogensen, Mogens. Sun . "Oxygen nonstoichiometry and transport properties of strontium substituted lanthanum ferrite". United States. doi:10.1016/j.jssc.2007.02.012.
@article{osti_21015800,
title = {Oxygen nonstoichiometry and transport properties of strontium substituted lanthanum ferrite},
author = {Sogaard, Martin and Vang Hendriksen, Peter and Mogensen, Mogens},
abstractNote = {This study presents an investigation of the properties of (La{sub 0.6}Sr{sub 0.4}){sub 0.99}FeO{sub 3-{delta}} (LSF40) covering thermomechanical properties, oxygen nonstoichiometry and electronic and ionic conductivity. Finally, oxygen permeation experiments have been carried out and the oxygen flux has been determined as a function of temperature and driving force. The electrical conductivity was measured using a 4 probe method. It is shown that the electrical conductivity is a function of the charge carrier concentration only. The electron hole mobility is found to decrease with increasing charge carrier concentration in agreement with recent literature. Values of the chemical diffusion coefficient, D{sub Chem}, and the surface exchange coefficient, k{sub Ex}, have been determined using electrical conductivity relaxation. At 800 deg. CD{sub Chem} is determined to be 6.2x10{sup -6}cm{sup 2}s{sup -1} with an activation energy of 137kJmol{sup -1}. The surface exchange coefficient is found to decrease with decreasing oxygen partial pressure. Oxygen permeation experiments were carried out. The flux through a membrane placed between air and wet hydrogen/nitrogen was J{sub O{sub 2}}{approx}1.8x10{sup -6}molcm{sup -2}s{sup -1} (corresponding to an equivalent electrical current density of 670mAcm{sup -2}). The oxygen permeation measurements are successfully interpreted based on the oxygen nonstoichiometry data and the determined transport parameters.},
doi = {10.1016/j.jssc.2007.02.012},
journal = {Journal of Solid State Chemistry},
number = 4,
volume = 180,
place = {United States},
year = {Sun Apr 15 00:00:00 EDT 2007},
month = {Sun Apr 15 00:00:00 EDT 2007}
}