Novel solid-state reaction route to synthesize Pb(Mg_1/3Nb _2/3)O₃-PbTiO₃ ceramics with a pure perovskite phase

Perovskite Pb(Mg1/3Nb2/3)-PbTiO3 (PMN-PT)ceramic powders were synthesized at relatively low temperatures with a one-time mixing solid-state reaction. Th synthesis was successfully done by simply introducing poly(ethylene glycol) (PEG) to the mixture of PbO, MgO, and Ti02. The perovskite, with a morphotropic phase boundary (MPB) compostion was synthesized, and the role of PEG in the crystallization was investigated. Both pyrochlore and perovskite phases were detected by X-ray diffraction (XRD) for the oxides mixed with PEG with molecular weight of 200, and calcined at 600 °C. The results indicate that with the increase of calcination temperature, PbO is involved in the formation of perovskite phase mainly by reacting with Ti02. This method can be applied to the synthesis of other Pb-containing and Bi-containing ferroelectric materials, especially the relaxors, in which the pyrochlore phase is difficult to eliminate.