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

Abstract

Abstract Nd 2 O 3 (0–0.8 wt.%)-doped (Bi 0.5 Na 0.5 ) 0.94 Ba 0.06 TiO 3 (abbreviated as BNBT6) lead-free piezoelectric ceramics were synthesized by conventional solid-state processes. The effects of Nd 2 O 3 on the microstructure, the dielectric, ferroelectric and piezoelectric properties were investigated. X-ray diffraction (XRD) data shows that Nd 2 O 3 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 Nd 2 O 3 become denser. The temperature dependence of the relative dielectric constant shows that Curie point does not change obviously with the addition of Nd 2 O 3 . At room temperature, the BNBT6 ceramics doped with 0.4 wt.% Nd 2 O 3 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 ɛ r of 1947 and dissipation factor tan δ of 0.057). Moreover, all BNBT6 − x (wt.%) Nd 2 O 3 ceramics exhibit a typical relaxor behavior with diffuse phase transition characteristics.