DESTRUCTION MECHANISMS IN CERAMIC MULTILAYER ACTUATORS

Destruction mechanisms were investigated in electrostrictor, piezoelectric and phase-change antiferroelectric ceramic multilayer actuators with an interdigital electrode configuration. Simultaneous observations were done by three different methods: visual observation with a charge coupled device (CCD) microscope, field-induced strain and acoustic emission (AE) measurements. During a cyclic electric field application, the crack was initiated from the edge of an internal electrode and propagated obliquely to another electrode in the piezoelectric sample, while in the antiferroelectric, the crack was initiated between a pair of electrodes and propagated parallel to the electrodes. The field-induced strain curve exhibited asymmetric and enhanced strains in all the samples during the crack propagation, probably due to the internal delaminations. The AE count also increased drastically before the destruction.