Microstructures and electrical properties of Bi0.5-(Na1−x−yKxLiy)0.5TiO3 lead-free piezoelectric ceramics

The microstructures and electrical properties of Bi0.5(Na1−x−yKxLiy)0.5TiO3 lead-free piezoelectric ceramics were studied. These ceramics were prepared by conventional ceramic technique. XRD analysis reveals that the ceramics possess almost pure perovskite phase when y⩽0.2. The SEM results show that, with more amounts of Li+, the crystalline grain growing speed is accelerated, and the sintering temperature can effectively be decreased. The measurements of piezoelectric properties indicate that the ceramics with relatively low amount of Li+ and high amount of K+ have comparatively large piezoelectricity. The dielectric measurements show that the ceramics have properties like relaxor ferroelectrics and diffuse phase transition (DPT) at Td and Tc, respectively. The results of ferroelectric measurements reveal the system has relatively higher remanent polarization Pr (27.6 μC/cm2) and lower coercive field Ec (37.5 kV/cm).