0.09(Bi0.5Na0.5)(0.94)Ba0.06TiO3-(0.01 - x) Bi-0.5(Na0.82K0.18)(0.5)TiO3-x BiAlO3 (BNBKT-xBA) lead-free piezoelectric ceramics were synthesized by conventional solid-state reaction processes. Structure, ferroelectric and piezoelectric properties of BNBKT-xBA ceramics were investigated. X-ray diffraction data shows that BNBKT-xBA ceramics form the pure perovskite phases and the ceramics have the morphotropic phase boundary when x <= 0.030. At room temperature, the BNBKT-xBA ceramics at x = 0.030 have better electrical properties, the piezoelectric constant d(33) and planar coupling factor k(p) of BNBKT-xBA ceramics reaches peak values at x = 0.030: d(33) = 217 pC N-1, k(p) = 0.308. The remnant polarization P-r, mechanical quality factor Q(m), and relative dielectric constant epsilon(T) of BNBKT-xBA ceramics at x = 0.030 attains 33.8 mu C cm(-2), 133 and 928 (100 KHz), respectively. As BA content increase, the depolarization temperature T-d shift toward lower temperature, and T-d of BNBKT-xBA ceramics with x = 0.030 decreased to 55 degrees C. (C) 2012 Elsevier B.V. All rights reserved.