Preparation and Electrical Properties of High-TC Piezoelectric Ceramics of Strontium-Substituted Bi(Ni1/2Ti1/2)O3-PbTiO3

A piezoelectric system of (1-x)Bi(Ni1/2Ti1/2)O-3-x(Pb(1-y) SryTiO3) (BNT-PST) is developed to have good high temperature piezoelectric properties with much improved resistivity. The crystal structure shows that the phase transformation from tetragonal phase to rhombohedral one is gradually shifted to the composition with high content of PT by the substitution of strontium. The problem of leakage current for the Bi(Ni,Ti)O-3-PbTiO3 can be well resolved by introducing the dopant of strontium. Both dielectric loss and DC resistivity can be much reduced not only at room temperature but also high temperature. An optimum composition of 0.53Bi(Ni1/2Ti1/2)O-3-0.47(Pb0.95Sr0.05) TiO3 is obtained to have a good potential application of high temperature piezoelectric (d(33) = 205 pC/N, E-C = 3.32 kV/mm, P-r = 41.2 mu C/cm(2)). Strontium could be a useful dopant for the studies on the high temperature piezoelectric ceramics in future.