Analysis of the state of poling of lead zirconate titanate (PZT) particles in a Zn-ionomer composite

The poling behaviour of tetragonal lead zirconate titanate (PZT) piezoelectric ceramic particles in a weakly conductive ionomer polymer matrix is investigated using high energy synchrotron X-ray diffraction analysis. The poling efficiency, crystallographic texture and lattice strain of the PZT particles inside the polymer matrix are determined and compared with the values for corresponding bulk ceramics reported in literature. The volume fraction of c-axis oriented domains and the lattice strain of the PZT particles are calculated from the changes in the integral intensities of the {200} peaks and the shift in the position of the {111} peaks respectively. It is shown that for an applied macroscopic field of 15 kV.mm¡1, the PZT particles are effectively poled, leading to a maximum n(002) domain reorientation volume fraction, of around 0.70. It is also found that a significant tensile lattice strain, e{111}, of 0.6% occurs in the direction of the applied electric field, indicating the occurrence of residual stresses within the 2–4 mm size diameter particles. Although lower than that observed in poled tetragonal PZT ceramics, this level of lattice strain does indicate that the PZT particles within the composite experience significant elastic constraint. The correlation between the poling induced structural changes and the macroscopic piezoelectric and dielectric properties is discussed.