Abstract
Lead titanate ceramics modified by (Bi, Na) as A site ion in the perovskite structure were fabricated by a conventional firing. Partial substitution to that ceramics by the 3rd component such as Pb(Mg, Nb)O3 or Pb(Fe, Nb)O3 was also investigated. Their lattice parameters, dielectric constants, piezoelectric constants and elastic constants were measured as a function of PbTiO3 content.
Some compositions with low relative permittivity (εs??200), high Curie point (Tc??390°C) and with high anisotropy in electromechanical coupling coefficient (kt/kp-6) were found among PbTiO3-(Bi1/2Na1/2)TiO3-Pb(Fe1/2Nb1/2)O3 system ceramics. Piezoelctric anisotropy was discussed on the basis of the tetragonality of crystal and the elastic properties of the poled ceramics.
