Synthesis, characterization and transducer applications of piezoelectric ceramic/polymer composite materials

A unique approach has been developed for preparing 0-3 Pb(Zr, Ti)O 3/epoxy piezoelectric composites with high piezoceramic PZT powder loading. PZT volume fractions loading up to 85% were achieved. The high PZT loading was attributed to a specific bimodal particle size distribution of the PZT powder and the effective removal of excessive epoxy. The particle packing (or loading) results were found to be in excellent agreement with the theoretical prediction based on the Ouchiyama and Tanaka model.; The dielectric properties of the composite materials were studied. The higher loading of the ceramic phase led to an increase in the dielectric constant of the composite system. A modified "brick wall" model was suggested to physically represent the microstructure of the composites. The mathematical expression derived from this model was used to predict the dielectric constant of the composites.; The poling behavior of the composite materials was also studied. The electric field distribution in the composite was found to be a function of the volume fraction and the resistivity of the individual components. The experimentally observed optimum poling temperature was found to be excellent agreement with the theoretical prediction based on the modified "brick wall" model.; The piezoelectric properties of the composites were determined. The piezoelectric strain coefficient, d33, of the composite was found to increase with increased volume fraction of PZT phase in an almost linear fashion. This experimental observation was found to agree well with the theoretical prediction based on the modified "brick wall" model. Other piezoelectric properties, such as electromechanical coupling factor, mechanical quality factor, and acoustic impedance were obtained through resonance measurements. The results suggested that these highly loaded PZT composites, with improved piezoelectric properties, might be suitable for integrated sensor/actuator applications.; The experimental results on the integrated sensor/actuator showed that the composite had good combined sensor/actuator functions in the vibration control system. The performance of the integrated sensor/actuator was found to depend on the geometric arrangement of the sensor and actuator.