(江苏科技大学 数理学院, 镇江 212003)
摘 要: 采用固相反应法合成了具有菱方钙钛矿结构的La0.9Sr0.1Al0.9Mg0.1O3-y(LSAM9191), 并使用直流四极法对其电导率与温度(600~1 000 ℃)和氧分压(10-1~105 Pa)的关系进行了测量。 通过掺杂, 样品的离子电导率得到了显著提高, 在900 ℃时LSAM9191的氧离子电导率为8.6×10-3 S/cm, 离子电导活化能为1.04 eV。 从电导率随温度和氧分压的变化关系分析可知, LSAM9191在低氧分压(<10-4 Pa)下是一个纯氧离子导体, 而在高氧分压(>10-4 Pa)下则是一个混合离子导体。 随着温度的升高, 其氧离子迁移数和离子导电区域都轻微增大。 LSAM9191在高温和低氧分压环境下是一个性能优良的氧离子导电材料。
关键字: 混合离子导体; 氧离子导体; 电导率; 铝酸镧
( School of Mathematics and Physics, Jiangsu University of Science and Technology, Zhenjiang 212003, China)
Abstract: La0.9Sr0.1Al0.9Mg0.1O3-y(LSAM9191) was synthesized by using a standard solid state reaction method. The electrical property of LSAM9191 was measured using the DC four-probe method as a function of temperature(600-1 000 ℃) and oxygen partial pressure(10-1-105 Pa). XRD results show that LSAM9191 is rhombohedral perovskite structure. Doping of Sr and Mg increases the ionic conductivity significantly. Oxide ion conductivity of LSAM9191 is 8.6×10-3 S/cm at 900 ℃, the activation energy is 1.04 eV.The analysis of the oxygen partial pressure (p(O2)) and temperature dependence of electrical conductivity shows that LSAM9191 is an oxygen ion conductor below 10-4 Pa and a mixed conductor above 10-4 Pa at 900 ℃. With increasing temperature, the ionic transference number and the ionic conduction region slightly increase. Thus, LSAM9191 is a promising material as an oxygen ion conductor at high temperature in low p(O2), it may possibly be used for monitoring oxygen activities in molten steel.
Key words: mixed conductor; oxygen ion conductor; electrical conductivity; LaAlO3