Effect of excess Bi2O3 on the electrical properties and microstructure of (Bi1/2Na1/2) TiO3 ceramics

Bi1/2Na1/2)TiO3 ceramics (BNT) with 0-6 mol% of excess Bi2O3 are prepared by conventional solid-state sintering. The electrical properties of the samples are examined. The addition of excess Bi2O3 reduces the leakage current of BNT ceramics significantly, thus facilitating the poling process, and improves their piezoelectric properties slightly for certain amounts of added Bi2O3. BNT ceramics have very high dielectric constants and dissipation factors at low frequency and high temperature due to their high conductivity. Adding excess Bi2O3 to BNT ceramics affects their dielectric behavior and phase transition temperatures. Grain growth is suppressed by adding Bi2O3 and no second phase is observed for BNT ceramics with up to 6 mol% of excess Bi2O3 added.