Mechanochemical synthesis of 0.9[9.6Pb(Zn1/3Nb2/3)O-3 center dot O.4Pb(Mg1/3Nb2/3)O-3]center dot 0.1PbTiO(3)

Lead zinc niobate-lead magnesium niobate-lead titanate (PZN-PMN-PT) ceramic powders of perovskite structure have been prepared via a mechanochemical p rocessing route. A single-phase perovskite powder of ultrafine particles in the nanometer range,vas successfully synthesized when a MZN powder (columb ite precursor) was mechanically activated for 10 h together with mixed lead and titanium oxides. The following steps are involved when the ternary oxi de mixture is subjected to an increasing degree of mechanical activation. F irst, the starting materials are significantly refined in particle size as a result of the continuous deformation, fragmentation and then partially am orphized at the initial stage of mechanical activation. This is followed by the formation of perovskite nuclei and subsequent growth of these nuclei i n the activated oxide matrix with increasing activation time. When calcined at various temperatures in the range of 500-800 degrees C, pyrochlore phas e was not detected by XRD phase analysis in the mechanochemically synthesiz ed powder. Only a minor amount (similar to 2%) of pyrochlore phase was obse rved when the calcination temperature was raised to 850 degrees C. The PZN- PMN-PT derived from the mechanochemically synthesized powder can be sintere d to similar to 98% relative density at a sintering temperature of 950 degr ees C, The PZN-PMN-PT sintered at 1100 degrees C for 1 h exhibits a dielect ric constant of similar to 18 600 and a dielectric loss of 0.015 at the Cur ie temperature of 112 degrees C when measured at a frequency of 0.1 kHz, to gether with a d(33) value of 323 x 10(-12) pC/N.