Fabrication And Characterization Of PZT Thick Films Based On Electrohydrodynamic Jet Deposition

PZT thick films are widely used in aerospace,medical diagnosis,electronic information and other fields due to their many advantages,such as strong driving force,wide frequency range,high sensitivity and strong compatibility.Electrohydrodynamic jet deposition is a kind of additive manufacturing technology based on the electric hydrodynamic effect,which uses the stable and fine jet to realize material depositing.The jet is generated by the fluid under the effect of electric field force and mechanical force.Electrohydrodynamic jet deposition has many advantages,such as high forming precision,strong controllability and wide material adaptability.In this paper,the polarization system for piezoelectric films was designed and built and the PZT composite suspension for depositing thick films was prepared.The PZT thick films were deposited on silicon substrate and characterized.The study of fabrication and properties of PZT thick films without substrate were carried out.First of all,the polarization system suitable for piezoelectric films and piezoelectric devices with micro-scale structures was designed and built.It can meet the key parameters of voltage,temperature and time to adjust and control.The PZT composite suspension was prepared by ball-milling and the influence of the ball-milling time on the physical properties of it was studied.The PZT composite suspension suitable for electrohydrodynamic jet deposition was obtained.Then,PZT thick films were deposited on silicon substrate by E-jet deposition and the relationship between the ratios or milling time of PZT suspension and the density of films was analyzed.The PZT suspension which was composed of 10 g PZT powder and 10 ml PZT sol was milled for 50 h.Then the dense and crack-free thick films were obtained,followed by sintering for pure perovskite structure at 720? for 20 min in air.And not only the density but also the electrical properties of the PZT thick films improved further by sol infiltrating.The remanent polarization(Pr)increased to 2.3 times and the dielectric constant(?)increased to 2.4 times in the frequency range of 1kHz to 100 kHz.Finally,the fabrication and characterization of PZT thick films without substrates were studied.The PZT thick films without Si substrate were obtained by wet etching and the effect of substrate materials on the electrical properties of PZT thick films was studied.It was found that the Pr and d33 of E-jet deposited PZT thick films increased to 2 times after etching Si substrate.In addition,the research on annealing technology and polarization properties of PZT fibers were carried out and the suitable annealing parameters and polarization parameters were determined.