Dielectric, Ferroelectric, and Piezoelectric Properties of Bi(Ni_(1/2)Ti_(1/2)) O_3-Modified BiFeO_3-BaTiO_3 Ceramics with High Curie Temperature

摘要

New piezoelectric ceramics, 0.71BiFe_(1-x)(Ni_(1/2)Ti_(1/2))_x O_3-0.29 BaTiO_3+0.6 wt% MnO_2 [BFNTx-BT] (x = 0-0.09), were fabricated using conventional mixed-oxide method. It was found that the introduction of BNT into BF-BT system caused insignificant change in crystal structure, which is a single-phase perovskite structure. However, an obvious variation in microstruc-ture took place. The ceramics with composition of x = 0.03 showed enhanced piezoelectric, electromechanical, and ferroelectric properties with piezoelectric constant d_(33) = 156 pC/N, planar electromechanical coupling factors A,, = 0.308, remnant polarization P_r = 22.5 μC/cm~2, and coercive field E_c = 28.2 kV/cm, with a high Curie temperature T_c = 431℃, respectively. The combination of good piezoelectric properties and high T_c makes these ceramics suitable for elevated temperature piezoelectric devices.