High temperature piezoelectric ceramics based on (1 − x)[BiScO3 + Bi(Ni1/2Ti1/2)O3] − xPbTiO3

High temperature ferroelectrics are an important aspect of piezoelectric material research for many energy related applications. Some of the desired properties are high Curie temperature, large remanent polarization, and large piezoelectric coefficients. Polycrystalline perovskite ceramics of the composition (1 − x)[BiScO3 + Bi(Ni1/2Ti1/2)O3] − xPbTiO3 (BS-BNiT-PT), were synthesized using standard solid state processing. Room temperature X-ray diffraction revealed a perovskite phase with an observed transition from tetragonal to pseudo-cubic symmetry over the compositional range x = 0.50–0.60. Compositions rich in PbTiO3 showed strong tetragonal distortions with characteristic first-order phase transitions. As the PbTiO3 content decreased dielectric measurements revealed large permittivities (er′ ~ 16,000) with relaxor characteristics up to 400 °C. Ferroelectric hysteresis measurements revealed remanent polarizations as high as 31 μC/cm2 at x = 0.52 with relatively low coercive fields of 25 kV/cm. The piezoelectric coefficients, mechanical quality, and planar coupling factors of the x = 0.54 composition were 376 pC/N, 13.4, and 0.148, respectively.

► MPB composition found between samples with 52 and 54 mol% PbTiO3.
► Curie temperature found to be around 300–400 °C.
► Solid solubility limited down to 50 mol% PbTiO3.
► Highest calculated piezoelectric coefficient was 376 pC/N.