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

The large-signal unipolar behavior of PZT is characterized under combined electrical, thermal, and mechanical loading. Maximum strain Smax and polarization Pmax feature a pronounced sensitivity on stress with a field-dependent peak evolving at around −50 MPa that is associated with enhanced non-180° 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° domain switching at high stress levels, Smax(σ) decreases at a faster rate than Pmax(σ). Accordingly, the electrostrictive coefficient Q11 is shown to be stress-dependent. This observation is rationalized with the stress-dependent change of domain processes. It is furthermore found that Q11 features a notable dependence on temperature, increasing from 0.018 m4 C−2 at 25 °C to 0.028 m4 C−2 at 150 °C under zero-stress. To assess the actuatoric efficiency, a novel figure of merit η* is defined to quantify the fraction of input energy utilized for mechanical work.

► Strain and polarization are measured under combined mechanical, thermal, and electrical loads.
► Electrostrictive coefficient Q11 is demonstrated to be a function of temperature and stress.
► A novel efficiency factor η* is defined, relating effective work to overall input energy.