Multilayer bender-type PZT-PZN actuator by co-extrusion process

A multilayer flextensional bender-type actuator, which was composed of five piezoelectric layers and one passive conducting layer, was fabricated using a co-extrusion process. A low-temperature sinterable PZN-PZT was used for the piezoelectric layer. The conducting inner electrode layers and passive bottom layer were fabricated by dispersing silver particles in the PZN-PZT matrix. For the co-extrusion process, piezoelectric and conducting feedrods were made separately by mixing them with polymers, which was followed by the formation of the initial feedrods. The initial feedrods were co-extruded through a reduction die to produce a continuous multilayer sheet. The binder was burnt out and, the multilayer green bodies were then sintered at 900 °C. The design was suitable not only for applying a high electric field with inner electrodes, but also for inducing a residual tensile stress on the piezoelectric layer. A multilayer actuator with dimensions of 50 mm × 20 mm × 0.84 mm generated a displacement of approximately 400 μm at 400 V, which is more than twice the displacement of a simple two-layer actuator with the same dimensions.