Preparation of PZN-Based Ceramics Using a Sequential Mixing Columbite Method

In this experiment Pb(Zn_1/3Nb_2/3)O₃(PZN)-BaTiO₃ (BT)-Pb(Zr_0.52Ti_0.48)O₃ (PZT) ceramics were prepared using solid state reactions via columbite method by mixing the relevant oxides and were processed employing conventional sintering techniques. Dielectric, ferroelectric and piezoelectric properties were evaluated and the corresponding microstructures were examined using transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). The experimental results imply that it is difficult to prepare PZN-PZT-BT ceramics with a full perovskite structure using a conventional columbite method, i.e., PZN was prepared using the columbite method and then mixed, calcined and sintered with PT, PZ and BT. A modified approach (MC) of mixing and calcining all B-site elements first, then mixing and sintering with all A site elements was adopted. Electrical properties were enhanced but a small amount of pyrochlore phase still exists. Finally, a mixing and calcining sequence (sequential mixing columbite, SMC) of well calcined B-site elements, firstly with BaO then with PbO was utilized. A full perovskite structure of the specimen with excellent electrical properties can be obtained. Microstructural investigations showed Ba segregation at triple junctions for IC and MC processes, implying that stabilization of the perovskite structure of the specimens was not completely achieved due to element segregation.