Synthesis of single phase 0.9Pb[(Zn0.6Mg0.4)(1/3) Nb2/3O3]-0.1PbTiO(3) by mechanically activating mixed oxides

A novel mechanochemical method has been successfully developed to synthesiz e nanocrystalline 0.9Pb[(Zn0.6Mg0.4)(1/3)Nb2/3O3]-0.1PbTiO(3) (PZN-PMN-PT) powders, lead zinc niobate-lead magnesium niobate-lead titanate, of perovsk ite structure from constituent oxides. For the first time, the formation of PZN-PMN-PT perovskite phase from the mixed oxides of PbO, ZnO, MgO, Nb2O5 and TiO2 was triggered by mechanical activation at room temperature, and th erefore the multiple phase-forming calcinations at elevated temperatures an d the subsequent milling are skipped. The resulting PZN-PMN-PT powder exhib its a high specific surface area of 10.86 m(2)/g with nanocrystallites of 1 0-15 nm in size and can be sintered to a density of 97% theoretical at 950 degrees C for 1 h. A maximum dielectric constant of 18 986 and a dielectric loss of 0.018 at the Curie temperature of 103 degrees C were measured for the PZN-PMN-PT at 0.1 kHz when it was sintered at 1100 degrees C for 1 h. A diffuseness parameter of 35 K was estimated, which reflects the microcompo sitional fluctuation in this relaxer ferroelectric. (C) 1999 Acta Metallurg ica Inc. Published by Elsevier Science Ltd. All rights reserved.