Piezoelectric and dielectric properties of CeO2-added (Bi0.5Na0.5)0.94Ba0.06TiO3 lead-free ceramics

The electrical properties of (Bi0.5Na0.5)(0.94)Ba0.06TiO3 ceramics have been improved greatly by adding some CeO2. At room temperature, the sample containing 0.4 wt% CeO2 shows a stronger ferroelectricity and a quite good performance: relatively large remanent polarization P-r = 37.7 muC/cm(2), relatively high coercive field E-e = 37.1 kV/cm, high piezoelectric constant (d(33) = 152 pC/N), high coupling factor (Kp = 34%), enhanced dielectric constant (epsilon(r) = 652) and low dissipation factor (tgdelta = 1.2%) at 1 kHz. X-ray diffraction shows that CeO2 diffuses into the lattice of (Bi1/2Na1/2)TiO3 to form a solid solution during sintering, but does not change co-existence of tetragonal and rhombohedral phases in (Bi1/2Na1/2)TiO3-BaTiO3 during sintering. Meanwhile, scanning electron microscope observation indicates that a small amount of CeO2 affects the microstructure. (C) 2003 Elsevier Science Ltd. All rights reserved.