Structure and electrical properties of (Bi0.5Na0.5)0.94Ba0.06TiO3–Bi0.5(Na0.82K0.18)0.5TiO3–BiAlO3 lead free piezoelectric ceramics

0.09(Bi0.5Na0.5)0.94Ba0.06TiO3–(0.01 − x) Bi0.5(Na0.82K0.18)0.5TiO3–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 d33 and planar coupling factor kp of BNBKT–xBA ceramics reaches peak values at x = 0.030: d33 = 217 pC N−1, kp = 0.308. The remnant polarization Pr, mechanical quality factor Qm and relative dielectric constant ɛr of BNBKT–xBA ceramics at x = 0.030 attains 33.8 μC cm−2, 133 and 928 (100 KHz), respectively. As BA content increase, the depolarization temperature Td shift toward lower temperature, and Td of BNBKT–xBA ceramics with x = 0.030 decreased to 55 °C.