Activation-induced pyrochlore-to-perovskite conversion for a lead magnesium niobate precursor

One or more pyrochlore phases are often involved as transitional phases pri or to the formation of the perovskite phase in lead magnesium niobate (PMN) precursors. The elimination of these pyrochlore phases requires careful co ntrol of the calcination temperature and therefore is often difficult to co mplete. We report on the pyrochlore-to-perovskite conversion triggered by m echanical activation in a freeze-dried PMN precursor. The resulting PMN pow der exhibits a well-established crystalline perovskite structure which is s table for calcination temperatures ranging from 400 degrees to 800 degrees C. A refined particle size in the range of 30-50 nm was obtained.