Microstructures and Electrical Properties of Bi_(0.5)-(Na_(1-x-y)K_xLi_y)_(0.5)TiO_3 Lead-free Piezoelectric Ceramics

The microstructures and electrical properties of Bi_0.5(Na_1−x−y K _x Li _y )_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 T _d and T _c, respectively. The results of ferroelectric measurements reveal the system has relatively higher remanent polarization P _r (27.6 μC/cm²) and lower coercive field E _c (37.5 kV/cm).