Effects of Bi2O3 additive on sintering process and dielectric, ferroelectric, and piezoelectric properties of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 lead-free piezoceramics

Lead-free Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) piezoceramics with Bi2O3 additive were synthesized using solid-state ceramic processing. Various amounts of Bi2O3 (0.05, 0.1, 0.5, and 1.0 mol%) were added after calcination, milled, compacted, and sintered with no compensation at A- or B-sites. Addition of up to 0.5 mol% Bi2O3 was found to greatly enhance the densification and increase the piezoelectric properties, while higher amounts decreased the grain size and induced relaxor-like electrical behavior, obeying the Vogel-Fulcher model. The highest properties were obtained for the BCZT with 0.1 mol% Bi2O3 sintered at 1350 degrees C: d(33) = 325 pC/m, d(33*) = 509 pm/V (at 3 kV/mm), k(p) = 0.42, and P-r = 10.4 mu C/cm(2). The microstructure, phase composition, and local structure were investigated by scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. The appearance of the A(1g) vibration mode in the Raman spectra and the shift of diffraction peaks to lower 2 theta values indicate the incorporation of Bi3+ into the B-site of the perovskite BCZT structure. (C) 2016 Elsevier Ltd. All rights reserved.