Multi functional device which combined a shape memory alloy and a piezo-electric material

The shape-memory alloy, for example NiTi (Nickel Titanium), is used for an actuator and frame by the shape- memory effect and the super-elasticity effect. And piezoelectric material, for example PZT (Lead Zirconate Titanate), is used for an actuator and sensor by the piezoelectric effect and the pyroelectric effect. However, each of the materials has been used for the sensor and the actuator independently because the principle of the function of each of materials is different. In this research, a new multi functional device combines these four functions is developed by coating the PZT thin film of 20μm to the surface of the NiTi wire by the chemical reaction by using the hydrothermal crystallization method. We succeeded in the detection of the displacement at a super-elastic deformation of this multi functional device from the piezoelectric effect of the PZT film on the surface. By combining each effects, the multifunctional device can be used for a self-sensing actuator, wherein the transformation by the shape-memory effect is detected by the piezoelectric effect or the pyroelectric effect, and the rough and precision actuator performs the rough movement by the shape memory effect and performs the precise movement by the piezoelectric effect.