Optimal working regime of lead-zirconate-titanate for actuation applications

Abstract

The large-signal unipolar behavior of PZT is characterized under combined electrical, thermal, and mechanical loading. Maximum strain S-max and polarization P-max feature a pronounced sensitivity on stress with a field-dependent peak evolving at around -50 MPa that is associated with enhanced non-180 degrees domain switching. As notable strains are achieved in excess of the quasi-statically measured blocking stress, it is suggested that the testing procedure presented within this work is suited to supplement blocking force measurements in order to comprehensively evaluate the electromechanical performance of a piezoceramic. With the suppression of non-180 degrees domain switching at high stress levels, S-max(sigma) decreases at a faster rate than P-max(sigma). Accordingly, the electrostrictive coefficient Q(11) is shown to be stress-dependent. This observation is rationalized with the stress-dependent change of domain processes. It is furthermore found that Q(11) features a notable dependence on temperature, increasing from 0.018 m(4) C-2 at 25 degrees C to 0.028 m(4) C-2 at 150 degrees C under zero-stress. To assess the actuatoric efficiency, a novel figure of merit eta* is defined to quantify the fraction of input energy utilized for mechanical work.