Synthesis and Characterization of Zr and Ca modified BaTiO3 Ferroelectric Ceramics

Abstract

During the last two decades, much effort has been given to developing new lead-free piezoelectric materials to replace the lead-based materials, such as PZT. The BaTiO3 ceramics have been investigated since 1950s, but most of the work focused on the capacitor, thermistor, and transducer applications. However, the BaTiO3 in its pure form exhibits the small permittivity, the poor piezoelectric properties, and low Curie temperature which have been the main obstacle to their wider commercial application. The recent discovery of the high dielectric and piezoelectric properties of Zr, Ca modified BaTiO3 (BZT-BCT) has stimulated a renewed interest in searching for environmentally friendly Lead-free ferroelectrics. However, there are certain critical issues relating to the practical use of BZT-BCT. It requires high phase formation temperature (1300oC) and sintering temperature (>1400oC) and has low Curie temperature (90oC). High sintering temperature may restrict the fabrication of multilayer devices. Very little work has been performed systematically to study the dielectric and piezoelectric properties of xBZT-(1-x)BCT at close compositional modifications around MPB. Keeping the above factors in mind, the primary objectives of the present work are to prepare Zr and Ca modified BaTiO3 at low temperature by exploring various powder preparation techniques and to optimize Zr and Ca content in BaTiO3 to get high dielectric and piezoelectric property. The other objectives are to lower the sintering temperature (<1200oC) of Zr and Ca modified BaTiO3 with additives and to study its dielectric property. In addition, it is also explored whether the MPB composition could be used to form a solid solution with BNT with an aim to improve the dielectric, piezoelectric properties and Curie temperature of parent or BNT.