Hermann Bödinger

Limitation of the degradation effect in piezoelectric multilayer actuators with ceramic layer thickness below 50 /spl mu/m

During the cofiring of PZT actuators, interactions between electrodes and ceramics occur that induce a degradation in the large signal piezoelectric properties for ceramic layer thicknesses below 50 /spl mu/m. It has been shown that the clamping forces applied to the ceramics due to thermal mismatch between the electrode and the ceramics are responsible for the reduction in the large signal piezocoefficient d/sub 33/ A shift in the ratio of electrode/ceramic layer thickness proved to be the best method to reduce the clamping forces applied to the ceramics. Consequently, an increase in d/sub 33/ of 50% could be achieved for samples with a 17 /spl mu/m ceramic layer thickness.