Dielectric and piezoelectric properties of (1 − x)(K_0.498Na_0.498Li_0.04)NbO₃–x(Bi_0.5Na_0.5)_0.9Ba_0.1(Zr_0.0055Ti_0.9945)O₃ lead-free ceramics

(1 − x)(K_0.498Na_0.498Li_0.04)NbO₃–x(Bi_0.5Na_0.5)_0.9Ba_0.1(Zr_0.0055Ti_0.9945)O₃ (KNLN–BNBZT100x, x = 0, 0.01, 0.02, 0.03, 0.05, 0.1) lead-free ceramics were prepared by conventional solid-state reaction technique. The influences of the BNBZT on the crystal structure, dielectric, and piezoelectric properties of the ceramics were investigated. The ceramics formed single-phase solid solutions with perovskite structure after sintering in air at 1050–1100 °C for 3–4 h. Morphotropic phase boundary (MPB) between orthorhombic and tetragonal phase was found in the composition range of 0.01 ≤ x ≤ 0.02. The Curie temperature, T_c, and the orthorhombic–tetragonal transition temperature, T_O–T, shifted to low temperature as BNBZT increased. The dielectric and piezoelectric properties of ceramics were enhanced for the composition near the MPB. The maximum value, 194 pC/N, of piezoelectric constant d₃₃ together with the mechanical quality factor Q_m, 20, were obtained when BNBZT content was 2 mol%.