Damage evolution in ferroelectric PZT induced by bipolar electric cycling

The fatigue behaviour of commercial bulk Lead Zirconate Titanate (PZT) indu ced by bipolar cycling was investigated. Polarisation and strain hysteresis loops as well as acoustic emissions (AE) were monitored. Higher cycling fi elds (2xE(c)) yield stronger fatigue, higher AE energy values and lower thr eshold values for the onset of AE events at high cycle numbers. AE amplitud es and energies were found to be a measure For the degree of domain damping . Cycling at 2 E-c leads to an increasing asymmetry of the strain hysteresi s, which is explained by an offset polarisation. Corrosion paths were obser ved by SEM, most numerously in the centre of a strongly fatigued sample. A damage scenario based on domain wall clamping due to the coalescence of poi nt defects is presented. (C) 2000 Acta Metallurgica Inc. Published by Elsev ier Science Ltd. All rights reserved.