Electroactive actuator materials: Investigations on stress and temperature characteristics

The quasistatic electromechanical and dielectric behaviors of different electroactive actuator materials are investigated under the simultaneous influence of uniaxial stress and temperature at high driving field. An experimental setup capable of applying 9000 newtons of uniaxial force was carefully designed, based on a precisely guided steel frame. Extra caution was taken to minimize the effects of mis-alignment and contact surface clamping. The materials examined in this study include a prospective PLSnZT antiferroelectric ceramics which is currently under development, as well as electrostrictive ceramics, namely PMN-PT 90/10 and PMN-PT 76/24. To assess the applicability of these materials in real systems, multilayer stacks were assembled and their response to stress and temperature was examined. The overall strain of the PLSnZT composition showed increases with increasing uniaxial stress. This might be the result of re-orientation of antiferroelectric domains under pre-stress. It also showed excellent stability in strain over the temperature range 20 to 75°C under stress as high as 100 MPa. In contrast, the electrostrictive ceramics are less dependent on stress than antiferroelectrics but more susceptible to temperature changes.