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

The perovskite solid solution system (1-x)BiScO/sub 3/-(x)PbTiO/sub 3/ represents an interesting new family of high-temperature piezoelectric materials. Compositions near the morphotropic phase boundary (x /spl sim/ 0.64) have been reported to have high Curie temperatures (T/sub c/ > 450/spl deg/C) and good piezoelectric coefficients (d/sub 33/ /spl sim/ 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/sub C/ to slightly lower temperatures (442/spl deg/C and 456/spl deg/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/sub ij/, c/sub ij/), piezoelectric (d/sub ij/, e/sub ij/, g/sub ij/, h/sub ij/), dielectric (/spl epsi//sub ij/, /spl beta//sub ij/), and electromechanical (k/sub ij/) coefficients and compare them to both unmodified 0.36BiScO/sub 3/-0.64PbTiO/sub 3/ and PZT5A ceramics.