【摘要】 探讨了PLZT铁电陶瓷的电疲劳特性及疲劳机理,测量并比较了室温下电疲劳前后材料的介电温谱及电滞回线以及疲劳试样在高于Curie温度之上保温数小时之后其室温下的介电温谱及电滞回线。测试结果表明疲劳试样在高于Curie温度之上保温数小时之后其室温下的介电温谱及电滞回线明显不同于电疲劳前试样的介电温谱及电滞回线,SEM分析表明疲劳前样品的断裂模式主要为穿晶断裂,而疲劳后样品的断口模式主要为沿晶断裂,利用原位XRD分析得出样品在交流电场下由90°畴变导致的畴变应变高达0.1％,这种反复高畴变应变造成的沿晶微裂纹,最终导致了铁电陶瓷的电疲劳。更多还原

【Abstract】 The electric fatigue property and fatigue mechanism of PLZT ferroelectric ceramics were studied. The dielectric constant and hysteresis loops for the non-fatigued sample were measured and compared with those for the fatigued sample at room temperature and with those for the fatigued sample annealed above the Curie temperature for hours. The experimental results show that the temperature dependences of dielectric constant and the hysteresis loops of the fatigued sample annealed above the Curie temperature for hours differ significantly from those of the non-fatigued sample, The SEM analysis indicates that the facture mode is mainly trans-granular for the non-fatigued sample, while inter-granular for the fatigue sample. The magnitude of strain due to the 90° domain reorientation during the application of an AC electric field, estimated from the in-situ XRD spectra, reaches as high as 0.1%. This repeated and high strain induced by the 90?domain reorientations ultimately leads to electric fatigue of the samples.更多还原