Combined wet-chemical process to synthesize 65PMN-35PT nanosized powders

Columbite MgNb2O6 precursors were synthesized by a wet-chemical method by means of the dissolution of Nb2O5.5H2O and magnesium carbonate in a solution of oxalic acid. Pure 65PMN-35PT powders could be obtained by the columbite method with the use of the partial oxalate and oxidant peroxo methods. Powders were characterized by X-ray diffraction and FT-Raman spectroscopy showing that pure 65PMN-35PT are obtained when the powders are calcined up to 800 deg. C, without any trace of Pb-Nb pyrochlore. Cubic Pb1,86Mg0.24Nb1.76O6.5 pyrochlore phase is formed by lead loss in the powders calcined at 900 deg. C and higher temperatures as undoubtedly characterized by Raman spectroscopy