Nb-modified Bi4Ti3O12 Piezoelectric for High Temperature Applications

Nb-modified Bi4Ti3O12 (BIT+xmol%Nb2O5) layer-structured piezoelectric ceramics were prepared by the solid state reaction method (at the pressure of about 12MPa). The quantity of grain growth along a-b plane is much more than that along c-axis with the increasing amount of Nb2O5. After Nb2O5 doping, the size of grain becomes small and unanimity. The electrical conductivity and dielectric loss are significantly reduced, while relative density, piezoelectric activity and electromechanical properties of Bi4Ti3O12-based ceramics are improved by the modification of Nb2O5. The electrical conductivity of BIT+4.00mol% Nb2O5 (10(-13)S/cm) decreases by 2 orders of magnitude compared with the undoped one. Besides, the BIT+4.00mol% Nb2O5 ceramic exhibits optimum electrical properties: relative density rho=98.7%, tan delta=0.23%, d(33)=18pC/N, Q(m)=2804, k(p)=8.1%, k(t)=18.6%, N-p=2227Hz.m and N-t=2025Hz.m, and the d(33) remains 17pC/N after annealing at 600 degrees C, which indicates that the ceramic is a potential material for high temperature applications.