Piezoelectric characteristics of spray-dried PZT ceramics modified by isovalent, supervalent and subvalent substitutions

Abstract

Abstract PZT powder of the composition Pb(Zr0.53Ti0.47)O3 was modified by the incorporation of Sr2+, La3+ and Fe3+ as isovalent, supervalent and subvalent cations respectively using spray drying technique. Powders were calcined and converted into piezoelectric ceramics by cold compaction, sintering and poling. Finished ceramics were characterized for their crystal structure, measured density, Curie temperature, polarization characteristics and electromechanical properties. It has been observed that the partial substitution of Pb2+ by Sr2+ increases the value of Qm and produces enhancement in other properties. Fe3+ when partially substituted for Zr4+ and Ti4+, lowers the values of ϵ tan δ, d 33 and kp and increases the value of Qm. On the basis of the influence of these substitutions on lattice parameters, densification characteristics, Curie temperature, coercive field and space charge field, it has been demonstrated that variation in the electromechanical properties is due to the presence of vacancies in the A and O positions of the ABO3 perovskite structure as well as variations in the lattice parameters.