Mechanochemical Synthesis of Lead Magnesium Niobate Ceramics in Iron Media

The possibility of mechanochemical synthesis of the lead magnesium niobate (PMN) powders of the composition Pb(Mg1/3Nb2/3)O3 in iron vials was investigated. According to X-ray and energy-dispersive spectroscopy (EDS) analysis of the obtained powder mixtures, milling in iron vials resulted in incorporation of Fe and formation of PFN of composition Pb(Fe1/2Nb1/2)O3 simultaneously with formation of PMN. Relative amounts of PMN and PFN were determined based on values of Curie temperature and lattice constant of perovskite phase. Although only 1 wt pct of Fe was incorporated, a stoichiometry of the system was significantly changed, resulting in formation of pyrochlore phase and excess MgO. Single-phase perovskite was obtained when the excess of PbO and Nb2O5 was added during mechanochemical synthesis. Because the dielectric properties were worse than expected, the alternative ways for improvement of dielectric properties were tried and discussed.