烧绿石型锆酸镧B位掺杂电学性能研究

Study on electrical properties of B-site doped La_2Zr_2O_7-based pyrochlore oxides

通过固相反应法,用M2O3(M分别为Er、Yb、Sc、Y、Gd)掺杂锆酸镧,研究了La2Zr2-xMxO7-!的电学性能,用扫描电镜和X-射线衍射仪对试样的微观结构和物相进行了分析,500～1000℃范围内在干氢气、湿氢气和空气气氛下测量电导率。实验结果表明,随着x的增加电导率也增大,当x=0.4时电导率达最大值,x值继续增加时电导率降低。在掺杂离子中,Yb掺杂的La2Zr2O7具有最大的电导率,700℃质子电导率为0.001S/cm。还研究了烧结时间对电导率的影响,烧结时间越长电导率越大。

La2Zr2-xMxO7-δ （M=Y, Sc, Er, Gd, Yb） system was investigated. La2Zr2O2-based pyrochlore-type oxides, which were partially substituted by Y203, Sc203, Er203, Gd203 and Yb203 respectively, were prepared by solid-state reaction. The phase identification was performed by X-ray diffraction （XRD）, and the microstructure of samples were examined by SEM. Conductivity measurements were carried out in the temperature range from 500 ℃ to 1 000 ℃ under wet hydrogen, dry hydrogen and air atmospheres, respectively. The results show that the conductivity increases with the increase of the doping level when a small amount dopant is added. La2Zr2-xMxO7-δ ceramics with x=0.4 had the highest conductivity. Yb doped La2Zr2O7 gained the highest proton conductivity of 0.001 S/cm at 700 ℃ among the observed ions doped La2Zr2O7. The effect of sintering time on electrical conductivity of La2Zr2-xMxO7-δ was also studied. The conductivity increased with the increasing of the sintering time.