Mechanochemically synthesized lead magnesium niobate

Abstract

Lead magnesium niobate (PMN) of high sintered density has been successfully prepared by a mechanochemical fabrication technique from mixed oxides of PbO, MgO, and Nb 2O 5. 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 constituent oxides are activated by mechanical energy instead of calcination at elevated temperatures. Nanosized PMN particles of perovskite structure with a minimized degree of particle agglomeration were formed when the oxide mixture was mechanically activated for 20 h. The resulting PMN powder was sintered to a density of ∼99% theoretical density at 1050°C for 1 h. The sintered PMN exhibited a peak dielectric constant of 18 080 at a frequency of 100 Hz at -11°C.