Study of a reduced and internally biased oxide wafer PZT actuator and its integration with shape memory alloy

Abstract

Large displacement piezoelectric actuators of a new kind—RAINBOW (reduced and internally biased oxide wafer) actuators, which are composed of reduced and unreduced layers—were prepared from PZT (Pb(Zrx Ti1−x )O3) by chemical reduction. The distribution of stress inside the RAINBOW structure and its actuating properties were both studied. It is found that the optimal ratio of reduced layer thickness for the RAINBOW structure is 0.3; reduced RAINBOW PZT has a lower resonance frequency and a three-times-larger displacement than traditional PZT; furthermore, the possibility of integration of PZT and SMA (shape memory alloy) was also explored. The PVD (physical vapor deposition) method was applied to deposit SMA coatings on the reduced layers of RAINBOW PZT patches. Results of mechanical and actuating experiments show that this is a reasonable idea for manufacturing actuators with better performance. (Some figures in this article are in colour only in the electronic version)