Direct preparation of K0.5Na0.5NbO3 powders

Abstract

K0.5Na0.5NbO3 powders have been directly synthesized by an alternative solid-state method. Stoichimometric mixture of ammonium niobium oxalate and C4H4O6KNa· 4H2O were calcined in temperature range from 500 to 800 °C for 3 h. The precursor and calcination products were characterized with respect to stoichiometry, purity, crystalline structure, particle size and powder morphology using X-ray diffraction (XRD), X-ray fluorescence (XRF) spectrometer, scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectra, thermogravimetric (TG) analysis, differential scanning calorimetry (DSC) and UV-Vis diffuse reflectance (UV-Vis) spectroscopy. XRD and XRF results reveal that stoichiometric K0.5Na0.5NbO3 powders could be synthesized by the method. The particle size is about 68 nm for the precursor calcined at 500 °C according to XRD data, which is in good agreement with SEM data. The average band gap energy is estimated to be 3.18 eV by UV-vis diffuse reflectance spectra. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.