Fabrication Of PZT-based Multilayer Piezoelectric Ceramic And Interface Optimization

Piezoelectric actuators have been largely applied in lots of areas,which include communication,electronic industry,and medical science et al,because of their several of excellent performances,such as high control precision,fast response,good linearity and low power consumption.Meanwhile,with the development of science,monolayer piezoelectric actuators cannot meet the current requirements of large displacement in the low applied voltage,because of their disadvantages of high applied voltage and small displacement.In order to overcome the shortcoming,multilayer piezoelectric actuators has attracted more and more attention.In this paper,the tape-casting process and the process of stacking,hot pressing and buried-pressing sintering process of preparing multilayer piezoelectric actuators are systematically studied.And we have found a good preparation process successfully.The interfacial defects between the layers of the multilayer ceramic actuators were optimized by using the method of doping ceramic powder with the internal electrode paste.The experimental results were also obtained successfully.The whole process of preparing multilayer piezoelectric actuators was studied systematically,focusing on the tape-casting process and the buried-pressing sintering process of the corresponding optimization.The result indicated that the prepared casting slurry meets the requirements of application when 0.9%wt dispersant,4.3%wt binder and 2.5%wt plasticizer were added in slurry with solvent comprised of methyl ethyl ketone and anhydrous ethanol with a volume ratio of 7:3.We can prepared the thickness of 50 microns of the good overall performance green sheet without obvious defects on surface when the casting machine heating substrate temperature is set to 38 ℃ or so,casting speed of 0.21 m / min-0.22 m / min,casting machine blade gap of 180μm.It is possible to satisfactorily suppress the deformation in the Z-axis direction and may not cause cracking of the multilayer piezoelectric actuators when loading 0.1875g/mm2 as the nuamber of multilayer piezo electric actuators less than 20 layers.A large number of pre-burning ceramic powder had been put around the actuator.Which could play a good suppression of X-Y direction of the lateral bending deformation.Then,the properties of the laminated samples prepared by successful sintering were tested.The results indicate that the sintered multilayer ceramics actuator shows distinct layers with few holes and gaps at the interface.The thicknesses of the piezoelectric and conducting layers are about 35 μm and 5 μm.At the same time,the interfacial improvement of multilayer ceramics was investigated by adding ceramic powders of different proportions to the internal electrode paste.The result indicated that the tensile strength of multilayer ceramic actuators increased by about 1.8-1.9 times during 30-40wt% adding amount.The square resistance of the started ESL903-A silver paste is 2mΩ/Sq,but the square resistance is about 40 mΩ/Sq during 40wt% adding amount.The silver layer became discontinuous while adding 50%wt amount of insulating piezoelectric powder.At this time,the internal electrode is substantially devoid of continuous electrical conductivity,and multilayer ceramic actuator had failed.At last,the fatigue properties of the specimens were also tested.The result shown that εr and d33 gradually decreased,the leakage current gradually increased with the amount of ceramic powder gradually increased.The experimental results are in good agreement with the model of the electrode connection of multilayer ceramic actuators.