Morphology and crystallinity of KNbO3-based nano powder fabricated by sol–gel process

Lead-free KNbO3 (KN) powder was fabricated by sol–gel process from metal alkoxides. KN precursor solutions were prepared by different preparation conditions such as the order of reflux process for alkoxides and the kinds of solvent. KN powders were sintered at 900 °C with a heating rate of 10 °C/min. Single phase KN powder was obtained using precursor solution prepared by reflux at 120 °C. We considered that the crystallinity of KN powder was affected by the dimer in Nb-pentaethoxide of the starting chemicals. On the other hand, grain shape of the KN powder also depended on the existence of secondary phase K4Nb6O17, and the grain size of the fine powder fabricated from precursor solution prepared by reflux at 80 °C using 2-methoxethanol and ethanol solvents was estimated to be about 500 nm and 1 μm, respectively.