铁电体电源中介质电阻特性及对输出电荷的影响

爆炸驱动铁电体脉冲电源利用铁电陶瓷在冲击压力作用下去极化释放电荷而产生电流，可以作为脉冲功率源的初始电源，也可直接驱动高阻抗负载产生脉冲高电压。通常情况下，铁电陶瓷可以看作理想的绝缘体，但在数GPa冲击波压力作用下，铁电陶瓷电阻率可能会明显下降并形成漏电导，使部分去极化释放电荷在铁电陶瓷内部流失，导致铁电陶瓷剩余极化电荷输出效率下降。以PZT95/5铁电陶瓷作为初始储能介质，以爆炸冲击波加载PZT95/5铁电陶瓷释放电荷对脉冲电容器充电，充电结束后电容器电压维持期间检测到明显的反向电流，根据铁电陶瓷输出电流和工作电压，得到冲击波作用过程中铁电陶瓷的瞬态电阻率曲线，并分析了电阻率下降对输出电荷的影响。进一步研究表明，冲击压力在铁电陶瓷边侧产生的稀疏波是引起电荷输出效率降低的主要因素，而铁电陶瓷电阻率下降对电荷输出效率的影响很小。

Resistivity properties of ferroelectric ceramics and its effects on output charges in explosion-driven ferroelectric generator

Explosion-driven ferroelectric generator (EDFEG) has important applications due to its excellent properties of high energy density and small volume. The output of EDFEG is based on the depolarization of ferroelectric during shock wave compression. In the present work, a new experiment method was developed to investigate dynamic resistivity of PZT95/5 under shock wave compression, in which a pulse capacitor was used as an output load. A current leakage in shocked PZT95/5 was observed in the experiment at a shock stress of 3.5 GPa after the depolarization of all ferroelectrics. This current leakage was just related to the resistance of shocked PZT95/5 and the voltage applied. The resistivity of shocked PZT95/5 was calculated for a longer time than the shock transit time of the sample. The factors that reduced the efficiency of output charge were analyzed. Furthermore, new experiments were designed to eliminate the effect on depolarization of ferroelectrics from boundary rarefaction. Two shots of experiments with different capacitance loads produced different voltages across the PZT95/5 ferroelectrics stack. These experimental results show that efficiency of output charge was improved obviously, and that the higher the electric field was, the more the resistance of PZT95/5 ferroelectrics decreased. In conclusion, the resistivity of ferroelectric ceramics has little effect on the efficiency of output charge from ferroelectric ceramics.