Composition Dependence of Crystallinity for Lead-Free (Li, Na, K)NbO3 Powder and Thin Films Fabricated by Sol-Gel Process

Lead-free Li x (Na0.5K0.5)1 − x NbO3 (LNKN) powder and thin film were fabricated by sol-gel process, and the composition dependence of crystallinity in LNKN was investigated. The precursor solution refluxed at 120°C was suitable for crystallization below 500°C. The crystalline LNKN powder and thin film were containing the secondary phase such as K3Li2Nb5O15 and K4Nb6O17, respectively. In case of the LNKN (x = 0.04 to 0.08) powder, K3Li2Nb5O15 phase was increased with increasing of Li content, and the relativity intensity of the X-ray diffraction (XRD) patterns was stronger than that of the bulk ceramics. However, K3Li2Nb5O15 did not emerged from thin film, since a compressive stress from the substrate might affect the behavior of Li+ ion.