Mechanochemically synthesized lead magnesium niobate

Lead magnesium niobate (PMN) of high sintered density has been successfully prepared by a mechanochemical fabrication technique from mixed oxides of P bO, MgO, and Nb2O5. The novel technique skips the phase-forming calcination steps at intermediate temperatures that are almost always required in the most widely employed columbite method. The solid-state reactions among cons tituent oxides are activated by mechanical energy instead of calcination at elevated temperatures. Nanosized PMN particles of perovskite structure wit h a minimized degree of particle agglomeration were formed when the oxide m ixture was mechanically activated for 20 h. The resulting PMN powder was si ntered to a density of similar to 99% theoretical density at 1050 degrees C for 1 h. The sintered PMN exhibited a peak dielectric constant of 18 080 a t a frequency of 100 Hz at -11 degrees C.