Study On Polarization And Properties Of Piezoelectric Ceramics/Polymer Composite Film

0-3 piezoelectric ceramic/polymer composite films have been widely used in transducer, ultrasonic medical imaging, hydroacoustic transducers, microelectromechanical systems (MEMS), structural health monitoring system (SHMS), etc.. However, it is difficult to pole the 0-3 piezoelectric ceramic/polymer composite films due to lower dielectric constant of the polymer matrix. As a result the composite system with excellent piezoelectric properties can not be easily obtained. One of the effective ways to increase in the polarization properties of 0-3 piezoelectric composite films is to enhance the dielectric constant and conductivity in the polymer matrix. In this article the graphite and polyaniline (PANI) were chosen as the dopant, and added into the system of 0-3 PZT/polymer composites. And the piezoelectric films were fabricated by hot-press and spreading method. The effect of graphite and PANI on the structure, polarization and electrical properties of the 0-3 piezoelectric composite films, and the relationship of composition, structure, properties were studied.The effect of graphite on the phase and microstructure of the 0-3 PZT/PVDF piezoelectric composite films is not obvious. The graphite is clearly separated from the polymer matrix. The dielectric constant of the polymer matrix may rapidly increase with an appropriate amount of graphite. And the polarization properties of PZT/PVDF piezoelectric film increase rapidly. The poled piezoelectric film with 0.8 vol.% graphite shows the highest relative intensity of (002) peak in XRD patterns and the highest remanent polarization in P-E curve. The dielectric constant and loss tangent of the doped 0-3 PZT/PVDF film increase quickly with the content of graphite. For the piezoelectric film with PZT of 50% volume fraction, the piezoelectric strain constant, planar electromechanical coupling coefficient increase while the mechanical quality factor decreases with the content of graphite. The three show the extremum values at 0.8% graphite volume fraction due to the optimal polarization properties of composites. Comparison with the value of the specimen without graphite, the piezoelectric constant of the piezoelectric film with 0.8% graphite nearly increases 50%.PANI can affect the phase and microstructure of 0-3 PZT/PVDF...