Microstructure and electrical properties of (Bi0.50+xNa0.50)0.94Ba0.06TiO3 ceramics with bismuth nonstoichiometry

A way to improve the piezoelectric properties of (Bi, Na)TiO3 ceramics is developed by suppressing the evaporation of Bi, and (Bi0.50+xNa0.50)0.94Ba0.06TiO3 (BNBT-x) ceramics were prepared by the conventional solid-state method. The effect of Bi nonstoichiometry on the microstructure and electrical properties of BNBT-x ceramics was investigated. A lower Tm value is demonstrated for BNBT-x ceramics with Bi nonstoichiometry, and a typical relaxor behavior is observed for BNBT-x ceramics with excessive Bi. The ceramic with x?=?0.01 has higher density and resistivity, and a macroscopic polarization can be induced that consequently can be subject to depolarization at a depolarization temperature. BNBT-x ceramics with Bi deficiency have a lower dielectric loss than that of those ceramics with Bi excess, while a smaller dielectric constant is observed for those ceramics with Bi deficiency. An enhanced piezoelectric behavior of d33?similar to?166 pC/N, k33 similar to 43.0%, kp similar to 33.9%, and Td?similar to?92 degrees C has been demonstrated for the ceramic with x?=?0.01. As a result, this is an effective way to improve the piezoelectric properties of (Bi, Na)TiO3 ceramics by compensating the loss of Bi.