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 solgel process, and the composition dependence of crystallinity in LNKN was investigated. The precursor solution refluxed at 120 degrees C was suitable for crystallization below 500 degrees 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.