冲击波垂向加载下 PZT 95／5铁电陶瓷的去极化和放电过程分析

摘要

电极化后的 PZT 95/5铁电陶瓷能够在冲击波作用下快速去极化并释放束缚电荷，形成高功率的瞬态输出电能。对于垂直于极化方向的冲击波加载情况，通过将去极化过程中的铁电陶瓷等效为电流源、电容和电导的并联电路，综合考虑冲击波压力对波速和去极化相变过程的影响，以及冲击波前、后铁电陶瓷的介电常数和电导率变化，建立了描述冲击波垂向加载下 PZT 95/5铁电陶瓷去极化和放电过程的模型，解析获得了铁电陶瓷的放电电流表述。在此模型基础上，开展了短路和电阻负载条件下 PZT 95/5铁电陶瓷在冲击放电过程中的输出电流特征分析，并与相关实验结果进行了对比。结果表明：模型能较好地模拟实验观测的铁电陶瓷 PZT 95/5的冲击放电过程，以及冲击波压力、负载电阻等对冲击放电输出电流的影响规律。%Bound charges of poled PZT 95/5 ferroelectric ceramics will be released under shock wave loading to form a high-power electrical energy output.For a shock loading perpendicular to the polari-zation direction,a model describing the depolarization and discharge process of PZT 95/5 ceramic by normal shock-wave is proposed in this paper.The effects of shock-wave pressure on the wave velocity and depolarization phase transition process were considered systematically.The depoling process of PZT 95/5 ferroelectric ceramics was analyzed by a parallel circuit with a current source,a capacitance and a conductance.The changes in the dielectric constant and conductivity during shock loading were taken into account.The output current characteristics of ferroelectric ceramics discharging process under short circuit and resistive load conditions,and the effects of changes in the dielectric constant and conductivity were analyzed and compared with the experimental results.The results show that the present theoretical model predicts well the discharge process of PZT95/5 ferroelectric ceramics under shock compression.