Dielectric breakdown of shock-loaded PZT 65/35

The dependence of dielectric breakdown in shock-loaded ferroelectric ceramics on both the shock amplitude and the electric field strength was investigated by employing shock reverberation techniques. In these experiments thick projectile disks were impacted on relatively thin specimens of hot-pressed PZT 65/35 [Pb0.99Nb0.02(Zr0.65Ti0.35)0.98 O3] poled to 10, 20, and 30 μC/cm2. The principal results of this investigation are: (i) dielectric breakdown is not explicitly a function of stress for stress values in the region of this study (<23 kbar), (ii) breakdown is not instantaneous, (iii) for fields greater than the breakdown threshold (≈5 kV/mm) the time between introduction of the shock into the ferroelectric and onset of breakdown decreases rapidly with increasing electric field, (iv) electric fields generated by 10-kbar shocks in specimens poled to 30 μC/cm2 are sufficient to cause breakdown, and (v) axial release waves can travel at a velocity as much as 15% faster than the initial stress wave.