Structure and electrical properties of (1 − x) (Na0.5Bi0.5)0.94Ba0.06TiO3–x BiAlO3 lead-free piezoelectric ceramics

(1 − x) (Na0.5Bi0.5)0.94Ba0.06TiO3–x BiAlO3 ((1 − x) BNBT6–x BA) lead-free piezoelectric ceramics were synthesized by conventional solid-state processes. Effects of BiAlO3 (BA) on the structure and electrical properties of (Na0.5Bi0.5)0.94Ba0.06TiO3 (BNBT6) ceramics were investigated. X-ray diffraction (XRD) data shows that (1 − x) BNBT6–x BA ceramics form the pure perovskite phases, and the ceramics have the morphotropic phase boundary (MPB) when x < 0.0500. At room temperature, the electrical properties of the BNBT6 ceramics have been improved with the addition of appropriate BA. At room temperature, (1 − x) BNBT6–x BA ceramics at x = 0.0225 have the highest remnant polarization (Pr = 42.5 μC/cm2), the highest piezoelectric coefficient (d33 = 204 pC/N), the highest planar coupling factor (kp = 0.3292), the highest dielectric constant (ɛr = 1687) and higher mechanical quality factor (Qm = 112).