Study Of Preparation Technology And Damping Property Of NiTi SMA/PZT Composite

In this paper, PZT piezoelectric ceramics are prepared by sol-gel on the NiTi SMA substrate. The new mechanisms of citric acid which replaces organic ether in preparation of PZT precursor are studied. The effect of different temperatures to crystallization of PZT ferroelectric ceramics is discussed by analyzing the X-ray diffraction peaks. The structure of the NiTi SMA/PZT composite material is studied by optical microscope and SEM. The effect of the three different interface states of NiTi SMA to the combination of NiTi SMA and PZT is discussed. The damping capability of NiTi SMA and NiTi SMA/PZT are studied with the swing resonance methods, and the rule of the damping capability which changes with the frequency and amplitude is investigated. The damping capability is contrasted between NiTi SMA and NiTi SMA/PZT. Their damping properties are interpreted with the movement of phase boundary and electric domain.It indicates that 650℃is the best sintering temperature. There is no pyrochlore phase. The main phase are PTZ ferroelectric ceramics phase. The TiO₂ transitional layer, which is formed in-situ by an oxidation reaction on the surface of the NiTi SMA at high temperature, provides a strong bond between PZT ceramic film and the NiTi SMA substrate. The combination of samples with corrosion is stronger than the polished and the oxidated.The damping capability of NiTi SMA/PZT changes greatly contrasted with NiTi SMA. The frequency response of NiTi SMA/PZT become widen. The frequency response of NiTi SMA is within the 0～7Hz,while the frequency response of NiTi SMA/PZT change to 0～20HZ.Furthermore,the damping value changes greatly. The effect of amplitude on damping capability of NiTi SMA/PZT is evident. There are different critical amplitudes to NiTi SMA and NiTi SMA/PZT. The former amplitude(excitation voltage) is 0.5v, while the latter is 1.0v. When the amplitude is lower than the critical amplitude, the damping increases significantly. When the amplitude is greater than critical amplitude the damping increases slowly. It indicates the latter hold the bigger load.The damping capability of NiTi SMA/PZT is integrated with NiTi SMA and PZT, which includes not only the movement of parent phase/ martensitic, but also the movement of electric domain. At the same time the piezoelectricity and the reverse piezoelectric of PZT piezoelectric ceramics strengthen the damping capability of NiTi SMA/PZT.