ZrO_2－Tb_2O_（3．5）－Y_2O_3氧化物体系的混合导电性和氧渗透

Mixed Electric Conduction and Oxygen Permeability of ZrO_2-Tb_2O_(3.5)-Y_2O_3 Oxide System

以电化学方法研究了ＺｒＯ２－Ｔｂ２Ｏ３．５－Ｙ２Ｏ３复合氧化物体系的混合电导和氧渗透性，并从固体缺陷化学的角度进行了讨论．结果表明，在所研究的组成范围内（Ｔｂ含量高达５０ｍｏｌ％），试样皆为面心立方萤石结构，其晶格常数随Ｔｂ含量增多而线性增大．Ｔｂ元素的变价及其随温度和组成的依赖关系决定了体系的混合电导性质．Ｔｂ含量的增多导致电子电导的增大，而Ｙ的掺入对其电性质的改善不明显．氧渗透性决定于材料电子电导和离子电导的综合作用，氧渗透通量较ＺｒＯ２－Ｙ２Ｏ３体系提高了１～２个量级．氧渗透过程机制遵循氧离子和电子空穴通过材料膜的体扩散为控制步骤这一模型．

The mixed electric conduction and oxygen permeability of ZrO2-Tb2O3.5-Y2O3 complex oxide system are studied by employing an electrochemical technique and discussed in terms of solid imperfection chemistry.The results show that the samples in the studied composition range (Tb content up to 50 mol%)are in fcc fluorite structure,and their lattice parameter linearly increases with Tb content. The valence variation of Tb element as well as its relations to composition and temperature determines the mixed electric conductivity of the specimens.The increase of Tb content leads to continuous increase of electronic conductivity.And,the addition of Y2O3 into the system does not show much effect on improvement of the mixed conduction. Oxygen permeability is determined by both oxygen ionic and electronic conductivity and the permeation flux is 1-2 order higher than that of ZrO2-Y2O3 system.The mechanism of the oxygen permeation is in agreement with the model of bulk diffusion control of oxygen ions and electron holes through the mixed conductor material.