The lead-free ceramics (Na0.54Bi0.5)0.94Ba0.06Ti1+xO3 with x = −0.02, 0, 0.02, and 0.04 were prepared by a solid-state reaction method. Effects of Ti4+ nonstoichiometry on crystallite structure, microstructure, dielectric, ferroelectric and piezoelectric properties were studied. The ceramics with x = −0.02 and 0 exhibit typical diffraction peaks of perovskite structure. A secondary phase appears in the ceramics with x = 0.02 and 0.04. The rhombohedral-tetragonal morphotropic phase boundary exists in all samples, and the relative amount of the tetragonal phase changes with the increase in the Ti4+ amount from deficiency to excess. Grain sizes and shape of the ceramics are unaffected by changes in Ti4+ nonstoichiometry. But, dielectric, ferroelectric and piezoelectric properties of the ceramics are close related to the Ti4+ amounts. Compared with the ceramic with x = 0, the ceramics with the Ti4+ nonstoichiometry have higher depolarization temperature, lower maximum dielectric constant, decreased piezoelectric constant and ferroelectric properties.

Keywords: Bismuth sodium titanate, Structure, Dielectric properties, Ferroelectric properties, Piezoelectric properties.