Research On1-3Type PZP/Epoxy Piezoelectric Composites

The purpose of this research is to fabricate a kind of highly performancedultrasonic probe piezoelectric material. Based on the ANSYS simulation results, twokinds of1-3type PZT/Epoxy piezoelectric composites with diffierent PZT-5Hvolume fraction (42.75%,56.25%) are prepared with a modified dicing and fillingmethod. The DC magnetron sputtering was used to deposit NiCr/Au films aselectrodes on the1-3type piezoelectric composites. The phase composition andstructures of the prepared composites were analysed by x-ray diffraction(XRD). Thethickness and surface morphology of the prepared NiCr/Au films were observed byscanning electron microscope(SEM). The resistivity of the NiCr/Au films weremeasured by hall effect tester(HMS). Finally, the precision impedance analyzer wasused to test the properties of the prepared1-3type composites.The ANSYS analysis results show that both the stress and displacementdistribution of the piezoelectric ceramic phase and epoxy resin phase are uneven.The stress of the piezoelectric ceramic phase is much greater than that of the epoxyresin phase, but the displacement of the piezoelectric ceramic phase is much smallercompared with the epoxy resin phase. For the piezoelectric ceramic phase, the stressand displacement in the middle part are smaller than that of its surrounding. And forthe epoxy resin phase, the stress and displacement in the vicinity of the piezoelectricceramic phase are small but get larger when the epoxy resin phase is away from thepiezoelectric ceramic phase. Moreover, we can also get the resonant frequency (Fs)and the anti-resonant frequency (Fp) of the designed composites.The cutting results show that the fracture rate of piezoelectric columns in thispiezoelectric composites is below the maximum permission value with the modifieddicing and filling method. In addition, the grinding efficiency and the quality of thegrinding composites could be ensured by the two-stage grind method.Finally, the surface quality and electrical property of the NiCr/Au compositefilm electrodes were measured, which show that within the electrode thicknessallowable value, the composite film electrode consisting of240nm NiCr alloy filmprepared by160W sputtering power and260nm Au film prepared by190Wsputtering power has a good surface quality and the lowest resistivity. After theperformance analysis for the prepared1-3type PZT/Epoxy piezoelectric composite,we found that the volume fraction of the piezoelectric phase have a significantimpact on the composites properties, which is consistent with the results obtainedfrom ANSYS analysis. It is also showed that the electromechanical coupling factorand acoustic impedance of the designed composites are both better than the pure PZT-5H piezoelectric ceramic. The electromechanical coupling factor could achieve68%while the acoustic impedance is14.47MRayls for the42.75%PZT-5Hcomposite, which is very suitable for highly performanced ultrasonic probe material.