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.
La0.6M0.4Fe0.8Cr0.2O3-δ（M=Ca, Sr, Ba） fine powders were synthesized by a glycinenitrate process（GNP）. BET test shows that the specific area of the obtained powders is over 20 m^2·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.
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
2005年第5期1132-1138,共7页
Journal of Inorganic Materials
基金
安徽省教育厅自然科学基金(2004kj326)
