Piezoelectric, ferroelectric and dielectric properties of Nd2O3-doped (Bi0.5Na0.5)0.94Ba0.06TiO3 lead-free ceramics

Nd2O3 (0-0.8 wt.%)-doped (Bi0.5Na0.5)(0.94)Ba0.06TiO3 (abbreviated as BNBT6) lead-free piezoelectric ceramics were synthesized by conventional solid-state processes. The effects of Nd2O3 on the microstructure, the dielectric, ferroelectric and piezoelectric properties were investigated. X-ray diffraction (XRD) data shows that Nd2O3 in an amount of 0.2-0.8 wt.% can diffuse into the lattice of BNBT6 ceramics and form a pure perovskite phase. SEM images indicate that all the modified ceramics have a clear grain boundary and a uniformly distributed grain size, and the BNBT6 ceramics doped with Nd2O3 become denser. The temperature dependence of the relative dielectric constant shows that Curie point does not change obviously with the addition of Nd2O3. At room temperature, the BNBT6 ceramics doped with 0.4 wt.% Nd2O3 show quite good performance with excellent piezoelectric properties (piezoelectric constant d(33) of 175 pC/N, planar coupling factor k(p) of 0.31 and mechanical quality factor Q(m) of 118) and enhanced dielectric properties (relative dielectric constant er of 1947 and dissipation factor tan delta of 0.057). Moreover, all BNBT6-x (wt.%) Nd2O3 ceramics exhibit a typical relaxor behavior with diffuse phase transition characteristics. (C) 2010 Elsevier B.V. All rights reserved.