Electroactive actuator materials: investigations on stress and temperature characteristics

Abstract

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°Cunder stress as high as 100 MPa. In contrast, the electrostrictive ceramics are less dependent on stress than antiferroelectrics but more susceptible to temperature changes.

Effect of Uniaxial Compressive Prestress on the Electromechanical Behavior of Lanthanum Modified Lead Zirconate Titanate Stannate Ceramic

“…The reduction of the strain is about 64.5% when the prestress is increased from 0 to 100 MPa. The longitudinal strain decreases with increasing prestress, which is different with some previous investigations 1,2 …”

“…The decrease of the dissipation energy will be explained by the following discussions. On the opposite, the forward transition electric field E A−F increases as the compressive prestress increases 1,2,19 …”

“…For alignment, the specimen is carefully emplaced at the center of the brass trough. The steel spherical washer below the alumina as an alignment fixture further minimizes transverse force caused by nonparallel sample surfaces or somewhere else 1,13,14 . The uniaxial compressive stress is supplied by a hand movement press.…”

“…The previous investigations on the stress‐dependent dielectric and electrical properties of many ceramic systems, such as PZT, PLZT, PMN, PMN–PT, PIN–PT, PZT–BT, PZT–PZN, and PMN–PZT 4–15 . However, there are very limited researches on antiferroelectric ceramics PLZST under uniaxial compressive prestress 1,2 . In this paper, the electromechanical behavior of La modified antiferroelectric ceramic PLZST under uniaxial compressive prestress is investigated.…”

“…This phase transition is accompanied with a large volume change associated with high longitudinal strain. The field induced strain is almost twice as large as that of conventional piezoelectric ceramics, making antiferroelectric ceramics the physics basis of many engineering applications 1,2 …”