【作者】 黄端平； 徐庆； 陈文； 张枫； 汪碧涛； 吉春艳；

【Author】 Huang Duanping, Xu Qing, Chen Wen, Zhang Feng, Wang Bitao, Ji Chunyan (School of Materials Science and Engineering , Wuhan University of Technology , Wuhan 430070 , China )

【机构】 武汉理工大学材料科学与工程学院；

【摘要】 采用甘氨酸-硝酸盐(GNP)法制备Ln0.6Sr0．4Co0.8Fe0.2O3(Ln=La,Pr,Nd,Sm)体系复合氧化物,研究A位稀土离子种类对该体系混合导电性能和热膨胀性的影响。研究结果表明,经700℃(保温1 h)热处理即可制得单相钙钛矿结构的Ln0.6Sr0.4Co0．8Fe0.2O3体系合成粉料,且合成粉料的颗粒细小均匀(-100 nm)。在室温-900℃范围内,Ln0.6Sr0.4Co0．8Fe0.2O3体系陶瓷的电子电导率随温度的升高在600℃附近达到最大值,氧离子电导率随温度的升高而单调增加。在相同温度下,随着Ln3+离子半径的减小,Ln0.6Sr0.4Co0.8Fe0.2O3体系陶瓷的电子电导率降低,离子电导率增加。Ln0.6Sr0.4Co0．8Fe0.2O3体系陶瓷的氧离子迁移数随温度的升高而增加,随Ln3+离子半径的减小而增加。在同一温度范围内,Ln0.6Sr0.4Co0．8Fe0.2O3体系陶瓷的平均热膨胀系数随A位稀土离子半径的减小而略有增大。更多还原

【Abstract】 Ln0.6Sr0.4Co0.8Fe0.2O3(Ln = La, Pr, Nd, Sm) powders were prepared by a glycine-nitrate process (GNP) , and the effect of the nature of lanthanide cations on the mixed conducting and thermal expansion properties of the resulting ceramics was examined . The result indicates that fine and uniform powders (-100 nm) with a pure perovskite structure can be produced by calcining at 700 ℃ for 1 h. The electronic conductivities of Ln0.6Sr0.4Co0.8Fe0.2O3 ceramics increase with measuring temperature through the maxi-mums near 600 ℃ and then decrease. The ionic conductivities of Ln0.6Sr0.4Co0.8Fe0.2O3 ceramics increase with temperature within the whole measuring tempera- ture range. At an identical measuring temperature, the electronic conductivities of Ln0.6Sr0.4Co0.8Fe0.2O3 ceramics degrade with the decrease in radius of Ln3+ cations due to the increase of lattice distortion, while the ionic conductivities enhance with the decrease in radius of Ln3+ cations. The ionic transport numbers of Ln0.6Sr0.4Co0.8Fe0.2O3 ceramics increase with measuring temperature and enhance with the decrease in radius of Ln3+ cations at an identical measuring temperature. In the case of a same measuring temperature range, the values of average thermal expansion coefficient (TEC) slightly enhance with the decrease in the radius of Ln3+ cations .更多还原