Investigations of co-existence region in lead zirconate-titanate solid solutions: X-ray diffraction studies

Compositions with varying Zr/Ti ratio in: xPbZrO3–yPbTiO3–zPb(Fe1/5, Ni1/5, Sb3/5)O3 such that (x+y+z)=100% and at constant z=10% were prepared by the conventional method of thermal synthesis of mixed-oxides. The characterization of these PZT ceramics was carried out with XRD and SEM. X-ray diffraction is presented to demonstrate the co-existence of the tetragonal and rhombohedral phases. In the present work it is shown that the tetragonal structure persists up to x=43, while the rhombohedral structure appears at x=46. These results suggest that the morphotropic phase boundary lies in the range 43<x<46 and therefore the width of the morphotropic transition is determined (Δx=3%). The lattice parameter measurements showed that tetragonal and rhombohedral unit cells of the phases depend on the sintering temperature. The effects of sintering temperature on microstructure are studied by means of a scanning electron microscope (SEM).