Structure and electrical properties of (1 − x) (Bi0.5 (Na0.82K0.18)0.5) TiO3-x BiAlO3 lead-free piezoelectric ceramics

► (1 − x) BNKT18-x BA ceramics were prepared by solid-state reaction method. ► Electrical properties of BNKT18 ceramics are improved by the addition of BA. ► (1 − x) BNKT18-x BA ceramics at x = 0.0075 have the best electrical properties. ► The optimized properties of the ceramics: Pr = 39 μC/cm2, d33 = 171 pC/N, kp = 0.31.