Structural, dielectric and piezoelectric properties of the ferroelectric PZT-BT ceramic compounds

Ceramic compounds of ferroelectric lead zirconate titanate (PZT) and ferroelectric barium titanate (BT) were prepared from nanopowders corresponding to the formula (1-x)PZT.xBT with x = 0; 0.1; 0.2 ... 0.9; 1. The samples were investigated by X-ray diffraction and electron microscopy and the piezoelectric properties were determined by means of an impedance analyzer. The sintering process is complex since samples densify at different temperatures depending on the composition resulting in different morphostructures. Accordingly, the piezoelectric properties show unusual behavior discussed in terms of different grain size and composition. A remarkably high enhancement of the relative dielectric constant, epsilon(r) coupled with maxima in both, piezoelectric charge constant d(33) and the piezoelectric voltage constant g(33), is observed for x = 0.4 while the values of the coupling coefficient kp are still high similar to those of pure PZT.