Study On Preparation And Properties Of 0-3 Type PZT/Polymer Piezoelectric Composites

0-3 type piezoelectric composites are fabricated with piezoelectric ceramic in shape of particles distributed in three dimensional connected polymer matrix. It overcomes the disadvantages of the brittleness of piezoelectric ceramic and the temperature limitation of polymer, and has a strong capability of being designed. It is widely used in the sensing field because it has small density and acoustic impedance and is easier to realize the matching between ceramic and transfer media. But the contact area between ceramic particles and matrix is big, and the interface of two phases is very poor. In addition, the dielectric constant of the polymer matrix is much smaller than that of piezoelectric ceramic, so it is not good for the composites to the polarized. Improving the matching of ceramic and matrix is necessary for enhancing the comprehensive performance of the composites.Lead zirconate titanate (PZT) is heat treated by different temperature, and piezoelectric composites are prepared with treated piezoelectric ceramics. High temperature treatment improves the piezoelectric activity and of PZT and improves the bonding state of matrix and ceramics, and also improves the overall performances of piezoelectric composites.Piezoelectric composites are prepared with different contents of PZT, the piezoelectric and dielectric constants and electromechanical coupling coefficient of composites increase with the increasing of ceramic content. The piezoelectric constant d33 is 20pC/N when the mass fraction of PZT is 90%, and the composites still have good flexibility.Polyurethane matrix is modified by epoxy resin, the piezoelectric constant of piezoelectric composites improves when the matrix is the interpenetrating network structure which is made up of cross-linking reaction using moderate epoxy resin and polyurethane. The d33 value improves by 4% when mass fraction of epoxy resin is 15%.Doping modification of the piezoelectric composites are conducted using different size carbon black. A moderate amount of carbon black can significantly improve the piezoelectric and dielectric properties of the composite., and the effects of different particle size of carbon black on composites are different. The d33 reachs its maximum with the carbon black particle size of 15 nm when the mass fraction of carbon black is 4%. However, the best content of the carbon black particle size of 30 nm is 5%. The corona polarization device was improved with increasing polarization needlepoint, the method of large area of polarization of piezoelectric composites is attempted which provides a new way for large area of polarization of composites. The sensing element preparated by piezoelectric composite has a good response to dynamic loads.