Three kinds of polymer materials, with varying hardness, were injected into porous PZT fabricated by the conventional sintering process to form a PZT/polymer composite with the majority of 3-3 connectivity. Such properties as the dielectric constant, the coupling factor, and the hydrostatic piezoelectric constants were studied. The effect of the polymer hardness on the properties of the composites also was investigated. Although the porous PZT exhibited much higher hydrostatic piezoelectric coefficient than conventional PZT and PZT/polymer composite, it is fragile for the processes such as silver pasting, electrical poling, and so on. The PZT/Polymer composite demonstrated a more promising mechanical strength than porous PZT. The mechanically soft polymer showed less degraded effects on the hydrostatic piezoelectric coefficient than the hard polymer.
