Fatigue resistant miniature piezoceramic actuators

Piezoelectric ceramics are desirable actuator materials for many biomedical applications due to their ability to generate precise, controlled motion with applied voltage. Herein, we report the fabrication of miniature piezoceramic actuators and their subsequent performance testing under high electric fields. Actuators were produced by tape casting sub-micrometer lead zirconate titanate (PZT) powder, followed by electroding, laminating, and dicing to form multilayer devices. The resulting devices consisted of ten active PZT layers, each of which was approximate to 50 mu m thick. To evaluate the effect of microstructure on performance, the components were heated to seven different temperatures ranging from 1175 to 1325 degrees C and held at each temperature for 24 min. Fatigue resistance was determined by monitoring changes in polarization during continuous cyclic operation. Actuators sintered at lower temperatures possessed smaller grains and exhibited improved fatigue resistance. In these specimens, polarization decreased by < 15% compared to more than 50% for devices processed at higher temperatures. These results indicate that sintering control can be effectively used to minimize performance degradation, improve reliability, and promote long-term stability.