Elastic, piezoelectric, and dielectric characterization of modified BiScO ₃-PbTiO ₃ ceramics

The perovskite solid solution system (1-x)BiScO ₃-(x)PbTiO ₃ represents an Interesting new family of high-temperature piezoelectric materials. Compositions near the morphotropic phase boundary (x ∼ 0.64) have been reported to have high Curie temperatures (T _c > 450°C) and good piezoelectric coefficients (d ₃₃ ∼ 460 pC/N). In this work, manganese additions were used to improve the high-temperature electrical resistivity and RC time constant of compositions near the morphotropic phase boundary. The addition of manganese was found to shift T _C to slightly lower temperatures (442°C and 456°C for x = 0.64 and x = 0.66, respectively). The piezoelectric activities of the modified materials were found to be reduced slightly due to the hardening effect of manganese; however, the temperature stability and resistivity of the modified materials were significantly enhanced. In this paper we present, for the first time, a complete set of materials constants, including the elastic (s _ij, c _ij), piezoelectric (d _ij, e _ij, g _ij, h _ij), dielectric ε _ij, β _ij), and electromechanical (k _ij) coefficients and compare them to both unmodified 0.36BiScO ₃-0.64PbTiO ₃ and PZT5A ceramics.