无机材料学报

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La0.6M0.4Fe0.8Cr0.2O3-δ(M=Ca、Sr、Ba)的制备表征及电性能

陈永红1,2; 魏亦军2; 高建峰1; 刘杏芹1; 孟广耀1   

  1. 1. 中国科学技术大学材料科学与工程系, 合肥 230026; 2。 淮南师范学院实验信息中心, 淮南 232001
  • 收稿日期:2004-08-16 修回日期:2004-09-24 出版日期:2005-09-20 网络出版日期:2005-09-20

Synthesis and Characterization of La0.6M0.4Fe0.8Cr0.2O3-δ(M= Ca, Sr,Ba) by GNP Method and Conductivity

CHEN Yong-Hong1,2; WEI Yi-Jun2; GAO Jan-Feng1; LIU Xing-Qin1; MENG Guang-Yao1   

  1. 1.Department of Materials Science and Engineering; University of Science and Technology of China; Hefei 230026, China; 2.Center of Experiment and Communication; Huainan Normal College; Huainan 232001, China
  • Received:2004-08-16 Revised:2004-09-24 Published:2005-09-20 Online:2005-09-20

摘要: 采用甘氨酸-硝酸盐法(GNP)制备了纳米尺寸的La0.6M0.4Fe0.8Cr0.2O3-δ(M=Ca、Sr、Ba)系列粉体.BET测试表明,合成粉体的比表面积>20m2·g-1;XRD结果显示,GNP法合成粉体在燃烧阶段物相已初步形成,La0.6Ca0.4Fe0.8Cr0.2O3-δ(LCFC)初粉经850℃热处理2h即转变为简单立方钙钛矿结构的纯相产物,1100℃下烧结体的相对密度即达95%,La0.6Sr0.4Fe0.8Cr0.2O3-δ(LSFC)、La0.6Ba0.4Fe0.8Cr0.2O3-δ(LBFC)初粉为双相结构,两者在低温段的烧结活性较LCFC差,1300℃以上相对密度接近95%.四端子法电导测试表明,掺杂样品的电导率较LaFeO3高2个数量级以上,700℃以下三者的电导率随温度的变化符合小极化子导电机理;800℃下LCFC的电导率>50S·cm-1,预示其可能成为IT-SOFC有实际应用前景的阴极材料.

关键词: 甘氨酸-硝酸盐法, La0.6M0.4Fe0.8Cr0.2O3-δM, 固体氧化物燃料电池, 阴极, 电导率

Abstract: La0.6M0.4Fe0.8Cr0.2O3-δ(M=Ca, Sr, Ba) fine powders were synthesized by a glycine-nitrate process(GNP). BET test shows that the specific area of the obtained powders is
over 20 m2·g-1. XRD test shows that the crystalline structure formed is at the stage of ignition by the method, the powder of La0.6Ca0.4Fe0.8Cr0.2O3-δ(LCFC) is pure cubic
perovskite-type after calcined at 850℃ for 2h, and its relative density (sintered at 1100℃) is 95%. The primary powders of LSFC and LBFC are with two-phase structure and with poor sintering
activities than that of LCFC at low temperature. The relative density of these ceramics sintered over 1300℃ is 95%. Four-probe technique tests indicate that the conductivity of doped-samples
is two orders of magnitude higher than that of LaFeO3, The changes of conductivity with temperature below 700℃ are in accord with the conduction mechanism of small polarons. The electrical
conductivity of LCFC at 800℃ is over 50 S/cm which indicates that LCFC may have potential application for IT-SOFC cathode.

Key words: GNP, La0.6M0.4Fe0.8Cr0.2O3-δM, Sr, Ba), IT-SOFC, cathode

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