Sr和Mg掺杂的LaAlO_3的合成及其离子导电性能

Synthesis and ionic conductivity of Sr and Mg doped LaAlO_3

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（600-1000℃）和氧分压（10^-1～10^5Pa）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^-3S／cm，离子电导活化能为1．04eV。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^-4Pa）下是一个纯氧离子导体，而在高氧分压（〉10^-4Pa）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。

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- 10^5 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.