Enhanced high-temperature piezoelectric properties of Bi(Zn0.5Ti0.5)O3-modified BiFeO3-BaTiO3 ceramics

This paper reports enhanced high-temperature piezoelectric properties of Bi(Zn0.5Ti0.5)O-3-modified BiFeO3-BaTiO3 (BF-BT-xBZT) ceramics prepared by two-step sintering method. The resultant ceramics show a symmetrical transition from a rhombohedral-pseudo-cubic (R-PC) phase coexistence to main PC phase with the increase of x, whose R-PC fraction (C-R/C-PC) is 53.3/46.7, 52.9/47.1, 50.2/49.8, 27.4/72.6, 15.3/84.7 when x = 0, 0.005, 0.01, 0.03, 0.05, respectively. The modification of BZT inhibits the grain growth, reduces the leakage current and gradually drives ferroelectric to relaxor transition. Optimal piezoelectric properties: d(33) = 193 pC N-1, P-r = 20.6 & mu;C cm(-2), T-C = 503 & DEG;C and k(p) = 36% achieved at x = 0.01 composition, which is due to the synergistic effect of an appropriate C-R/C-PC ratio, improved insulation and good polarization performance. In addition, the depolarization temperature T-d is close 280-312 & DEG;C, and the high-temperature d(33) further increases to 286-347 pC N-1, which shows a good application prospect of lead-free piezoceramics at high temperature. Our work also confirms that the addition of (Zn0.5Ti0.5)(3+) and two-step sintering method are an effective and convenient strategy to improve the high-temperature electrical performance of BiFeO3-BaTiO3 based lead-free ceramics.