Experimental Research On Curved Piezoelectric Structure By Electrohydrodynamic Jet Printing

Curved piezoelectric structures can realize the omnidirectional perception,response and conversion of spatial information due to their three-dimensional configuration.And they have been widely used in the fields of aviation and navigation,industrial control,biomedicine and so on.At present,the preparation process of the small-sized curved piezoelectric structure is complicated,and the preparation consistency is poor.As a high-resolution,non-contact additive manufacturing technology,electrohydrodynamic jet printing technology is widely used in the printing of different micro-size and complex structures.And the films structure prepared by it have small feature size,high microscopic quality and simple preparation process.Aiming at the problems of preparation of curved piezoelectric structures and the application characteristics of electrohydrodynamic jet printing technology,this thesis studies the experimental preparation of curved piezoelectric thick film structures based on electrohydrodynamic jet printing technology,and analyzes and then evaluates the performance of the fabricated structures.In this thesis,firstly,the application of curved piezoelectric structures and the problems in the preparation process are summarized.The problems and requirements faced by the electrohydrodynamic jet printing technology used in the preparation of curved piezoelectric thick films were analyze According to the results of the analysis,hemispherical and semi-cylindrical thick films preparation motion devices were designed.The movement trajectories of the preparation of thick films with hemispherical and semi-cylindrical surface structures are designed,and the effect of the hemispherical thick films preparation movement device was verified.Two kinds of curved motion devices were integrated and a curved motion platform was built.The electrohydrodynamic jet printing preparation software for curved piezoelectric thick films was developed.Secondly,the PZT composite suspension used for the preparation of curved piezoelectric thick films by electrohydrodynamic jet printing was prepared.The titanium alloy?TC4?material was selected to make the curved structure substrate,and the characteristic dimensions of the curved substrate were measured.A hemispherical piezoelectric thick film was prepared by electrohydrodynamic jet printing technology.And after annealing and sintering,electrode preparation and polarization treatment,the hemispherical PZT piezoelectric structure was obtained.Finally,the structural characteristics of the hemispherical curved PZT piezoelectric thick films and the piezoelectric and dielectric properties of the hemispherical curved piezoelectric structure are characterized and the response signal of the hemispherical piezoelectric structure is tested.Structural characterization shows that the surface quality of the hemispherical PZT piezoelectric thick film is good,the thick film has low porosity and good uniformity.The performance characterization shows that the prepared piezoelectric strain constant d₃₃ of the hemispherical PZT piezoelectric structure with a film thickness of 30?m and a radius of 4mm is about 60pC/N,The relative dielectric constant is about 225 and the mechanical loss is about0.0215.at the test frequency less than 1.1MHz.The response signal test shows that the hemispherical piezoelectric structure can generate a voltage signal response with the same trend as the external pressure signal changes,and the output voltage can reach 70mV.This shows that the process of preparing a curved piezoelectric structure by electrohydrodynamic jet printing is feasible.