铁电陶瓷的电疲劳机理研究

Electric Fatigue Mechanism of Ferroelectric Ceramics

研究了PMN—PNN－PZ－PT和PLZT铁电陶瓷的电疲劳特性及其疲劳机理。研究结果表明，疲劳与所加的疲劳电压大小有很大关系。当电压较小时，疲劳不明显；当电压较大时，疲劳加剧。疲劳机理主要是空间电行在畴壁的钉扎；陶瓷体和电极之间的电化学反应；缺陷在电场作用下的运动和Ag离子在较高电场作用下在陶瓷体内的迁移。显微结构观察证明了这些机制的存在。

The fatigue Property and fatigue mechanism of PMN - PNN - PZ - PT and PLZT ferroelectric ceramics were studied in this pa-per. The research results show that the fatigue of this kind of ferroelectric ceramics has tight connection with the level of the voltage. The fatigue is lighter at lower alternating voltage, and can recovery gradualjy itself. The fatigue becomes more remarkable at higher voltage.The fatigue mechanisms in the studied system were space charge .pinning at the domain wall, the electrochemical reaction between ce-ramics and electrode, the movement of the defect driven by the field and the immigration of silver ion in ceramics under high electric field.These mechanisms were proved by microstructure observation.