SYNTHESIS AND CHARACTERIZATION OF LEAD-FREE SODIUM NIOBATE POWDER.

Sodium niobate (NaNbO3) fine powders were synthesized by hydrothermal method using ammonium niobate (V) oxalate hydrate (C₄H₄NNbO₉ x H₂O), sodium hydroxide (NaOH) and sodium citrate hydrate (C₆H₉Na₃O₉) as precursors. The samples were characterized by X-Ray diffraction (XRD), scanning electron microscopy (SEM), AFM (Atomic Force Microscopy), UV-VIS spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR). X-ray diffraction for powder obtained by hydrothermal method revealed three phases mixture (NaNbO₃, Nb₂O5, Na₂C₂O₄). In order to obtain a material with perovskite structure, the powder was treated for 6 h at 600°C. After calcination, the X-ray powder diffraction (XRD) patterns shown reflections of a pure cubic structure (space group Pm-3m) with lattice parameters (a=b=c=3.909Å) comparable to those reported in the literature. The average particle sizes estimated by SEM image were 2-3 micrometers. [ABSTRACT FROM AUTHOR]