Oxygen nonstoichiometry and transport properties of strontium substituted lanthanum ferrite

被引：180

作者：

Sogaard, Martin ^{[1
]}

Hendriksen, Peter Vang ^{[1
]}

Mogensen, Mogens ^{[1
]}

机构：

[1] Riso Natl Lab, Fuel Cells & Solid State Chem Dept, DK-4000 Roskilde, Denmark

来源：

JOURNAL OF SOLID STATE CHEMISTRY | 2007年 / 180卷 / 04期

关键词：

oxygen ion diffusion; strontium substituted lanthanum ferrite; electrical conductivity relaxation; oxygen nonstoichiometry; thermal expansion; oxide ion conductivity; LSF; oxygen permeation; perovskite;

D O I：

10.1016/j.jssc.2007.02.012

中图分类号：

O61 [无机化学];

学科分类号：

070301 ; 081704 ;

摘要：

This study presents an investigation of the properties of (La(0.6)Sr(0.4))(099)FeO(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(Chem), and the surface exchange coefficient, k(Ex), have been determined using electrical conductivity relaxation. At 800 degrees C D(Chem) is determined to be 6.2 x 10(-6) cm(2) s(-1) with an activation energy of 137kJ mol(-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 Jo(2) approximate to 1.8 x 10(-6) mol cm(-2) s(-1) (corresponding to an equivalent electrical current density of 670 mA cm(-2)). The oxygen permeation measurements are Successfully interpreted based on the oxygen nonstoichiometry data and the determined transport parameters. (c) 2007 Elsevier Inc. All rights reserved.

引用

页码：1489 / 1503

页数：15

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