Phase Transition, Thermal Expansion and Electrical Properties of BNLT-BT Ceramics Near the Morphotropic Phase Boundary

Lead-free ceramics based on bismuth sodium lanthanum titanate (Bi0.4871Na0.4871La0.0172TiO3: BNLT) and barium titanate (BaTiO3: BT) were prepared by a modified two-step mixed-oxide method. Effects of BT content on the phase transition, thermal expansion behavior, mechanical and electrical properties of lead-free BNLT-BT ceramics were studied. The Burn's temperature and local polarizations were estimated from the thermal expansion data. Various aspects of understanding the polarization behavior and other effects in this system have also been investigated and discussed. The 0.96BNLT-0.04BT ceramics have shown the d33 value of 135 pC/N. The coercive field (E c) and remanent polarization (P r) were found to be 24 kV/cm and 9.0 mu C/cm2, respectively. This may be useful in the future development of multifunctional lead-free materials in electronic applications.