Soft/hard PZT monolithic bi-layer composite actuator

Lead Zirconate Titanate (PZT) is a well-known piezoelectric material which has been widely used for transducer, sensor and actuator applications. According to the compositional modifications near morphotropic phase boundary, PZTs can be classified into two types, soft PZT and hard PZT, which are distinguished by the piezoelectric properties. Therefore, the combination effect of the strain-E-field response of soft/hard PZT composite actuator has been much interested to be observed. In this study, two types of soft PZTs (PZT-610HD and PZT KP 60) and two types of hard PZTs (PZT-TISTR and PZT DPZ-HQ) were used. The ratio of the soft and hard PZT powders used to form bi-layer composite was designed for 1:1. The bi-layer composites were prepared by co-pressing and co-sintering to obtain the monolithic layer between the two layers. The displacement and electromechanical properties of all bi-layer composites actuators were investigated compared to the soft and hard PZT single layer counterparts. For an application of bi-polar E-field at 10 kV/cm, a maximum peak displacement (11 μm) was obtained from the bi-layer composite actuator prepared by 610HD-TISTR powders, while the displacement of soft and hard PZT single layer was shown at 1 μm and 0.4 μm, respectively. This can be discussed in terms of the sintering behavior as well as the ferroelectric properties of those soft and hard PZTs which affect the displacement response.