Oxygen nonstoichiometry and ionic transport properties of La0.4Sr0.6CoO3-δ

被引：17

作者：

Sitte, W ^{[1
]}

Bucher, E

Benisek, A

Preis, W

机构：

[1] Graz Univ Technol, Inst Phys & Theoret Chem, A-8010 Graz, Austria

[2] Univ Leoben, Inst Phys Chem, A-8700 Leoben, Austria

来源：

SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY | 2001年 / 57卷 / 10期

基金：

奥地利科学基金会;

关键词：

oxygen; -nonstoichiometry; chemical diffusion coefficient; ionic conductivity; materials; La0.4Sr0.6CoO3-delta; LSC;

D O I：

10.1016/S1386-1425(01)00489-9

中图分类号：

O433 [光谱学];

学科分类号：

0703 ; 070302 ;

摘要：

Homogeneous samples of La0.4Sr0.6CoO3.delta Were obtained by the glycine nitrate process. The oxygen nonstoichiometry was determined from oxygen exchange measurements as a function of oxygen partial pressure (10(-4) bar < PO2 < 10(-2) bar) and temperature (300 degreesC < T < 900 degreesC). The chemical diffusion coefficient (D) over tilde was obtained from oxygen exchange measurements applying a stepwise variation of the oxygen partial pressure of the ambient atmosphere of a disk-shaped sample. The amount of oxygen absorbed or desorbed by the perovskite was analyzed as a function of time. Chemical diffusion data Were evaluated using simplified and exact fitting procedures taking into account the surface exchange coefficient. Alternatively, galvanostatic polarization measurements were performed in a P-O2-range between 10(-4) and 10(-2) bar to yield (D) over tilde and the ionic conductivity sigma (i) from the long time solution of the diffusion equation. Values for (D) over tilde from polarization measurements at T = 775 degreesC and from oxygen exchange measurements at T = 725 degreesC are in good agreement with each other. (D) over tilde and sigma (i) increase with increasing P-O2 (10(-4) to 10(-2) bar). The ionic conductivity shows a maximum at 3-delta approximate to 2.82 and decreases with decreasing oxygen content indicating the possible formation of vacancy ordered structures. (C) 2001 Elsevier Science B.V. All rights reserved.

引用

页码：2071 / 2076

页数：6

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