Phase transition behaviour and physicochemical properties of KNbO3 ceramics

We report herein the synthesis and morpho-structural properties of potassium niobate (KNbO3) nanopowders obtained by sol-gel starting from C4H4NNbO9·H2O (ammonium niobate (V) oxalate hydrate), KOH (potassium hydroxide) solution, citric acid (used as a chelating agent) and ethylic alcohol (used as a gelling agent). The thermal behaviour of the KNbO3 compound was studied by thermo-gravimetric analysis (TG/DTG) at different temperatures and atmospheres. Moreover, different thermal treatments at 300, 450, 600 and 800 °C were performed in order to study the thermal stability of the powders obtained, whose morphology, particle size, structure and degree of crystallization were comparatively characterized by X-Ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and scanning electron microscopy (SEM).