Effects of substitution in A- and B-site cations of Bi/sub 0.5/Na/sub 0.5/TiO/sub 3/

Abstract

Bismuth sodium titanate (Bi/sub 0.5/Na/sub 0.5/TiO/sub 3/), BNT, with a small amount of additives including La, Sm, Nd, and Nb were prepared by a conventional mixed oxide method. Powders of all compositions were calcined at 800/spl deg/C for 2 hrs to form a pure perovskite phase. All specimens were sintered at 1150/spl deg/C for 2 hrs to achieve at least 95% theoretical densities. Samples of the BNT with La modification exhibited a dielectric permittivity of 515, electromechanical coupling factors k/sub t/ of 45% and k/sub p/, of 13%, and a piezoelectric charge coefficient d/sub 33/ of 100. The properties of the La-modified BNT suggest that these compositions are potential candidates for hydrophone applications.