Structure and electrical properties of (1 − x)(Na0.5Bi0.5)0.94Ba0.06TiO3–xSmAlO3 lead-free piezoelectric ceramics

(1 − x)(Na0.5Bi0.5)0.94Ba0.06TiO3–xSmAlO3 [(1 − x)BNBT6–xSA] lead-free piezoelectric ceramics were synthesized by conventional solid-state method. Effects of composition on the micro-structure and electrical properties of (1 − x)BNBT6–xSA ceramics were investigated. X-ray diffraction data shows that (1 − x)BNBT6–xSA ceramics form the pure perovskite phases, and the ceramics have the morphotropic phase boundary when x ≤ 0.0100. At room temperature, the electrical properties of the BNBT6 ceramics have been improved with the addition of appropriate SA. At room temperature, (1 − x)BNBT6–xBA ceramics at x = 0.0100 has the highest remnant polarization (Pr = 47 μC/cm2), the highest piezoelectric coefficient (d33 = 179 pC/N), the highest planar coupling factor (kp = 0.296), the higher dielectric constant (ɛr = 1154) and higher mechanical quality factor (Qm = 131).