Contribution of (Bi0.45Y0.05)Na0.5ZrO3 to induced multiphase coexistence and enhanced piezoelectric properties of K0.5Na0.5NbO3 lead-free ceramics

In this study, new lead-free piezoelectric ceramics (1 x)(K0.5Na0.5)NbO3 (KNN)-x(Bi0.45Y0.05)Na0.5ZrO3 (BYNZ) were prepared using the conventional solid-state method, and the relation between the doping amount of (Bi0.45Y0.05)Na0.5ZrO3 and its structural and electrical properties was investigated. Material characterization and structural analyses conducted using X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy revealed that KNN-BYNZ ceramics formed single perovskite structures at 0 <= x <= 0.05 and a polycrystalline phase boundary (PPB) for the coexisting orthorhombic and tetragonal phases at 0.03 <= x <= 0.05. The ceramics exhibited desirable electrical properties at x = 0.04 (d(33) = 305 pC/N, k(p) = 45.8 %, epsilon(r) = 1316, tan delta = 2.4 %, T-c = 332.C, P-r = 28.2 mu C/cm(2), and E-c = 1.07 kV/mm). These findings reveal that the introduction of BYNZ enables the effective formation of a PPB in the KNN-based ceramics to improve their electrical properties, and they exhibit potential for replacing lead-based piezoelectric ceramics in the market.