Hydrothermal preparation and characterization of sheet-like (KxNa1-x)NbO3 perovskites

(KxNa1-x)NbO3 (KNN) powders with sheet-like morphologies were successfully prepared by the hydrothermal synthesis route combined with subsequent heat-treatment processes. When the heat-treated temperature was 600 degrees C, the (KxNa1-x) NbO3 (0.6 <= x <= 0.7) perovskite sheets were obtained in the KNN powders. The surface morphology and crystal structure of the KNN sheets were investigated by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM), respectively. The KNN sheets were in a well-defined hexagonal shape with a thickness of about 100-200 nm and a diameter of 1.5-3 mu m. The chemical structure of the KNN sheets was analyzed using Fourier Transform infrared spectroscopy (FTIR) and Raman spectroscopy. A growth mechanism for the sheet-like microstructures was discussed. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.