文摘
New (1 – x − y)Bi0.5Na0.5TiO3-xY0.5Na0.5TiO3-yBaTiO3 lead-free ceramics have been prepared by a conventional ceramic fabrication technique, and their structure and electrical properties have been studied. A morphotropic phase boundary (MPB) of rhombohedral and tetragonal phases is formed at 0.04 < y < 0.10. As compared to pure Bi0.5Na0.5TiO3 ceramic, the partial substitutions of Y3+ for Bi3+ and Ba2+ for (Bi0.5Na0.5)2+ in the A-sites of Bi0.5Na0.5TiO3 lower effectively the coercive field E c and increase the remanent polarization P r of the ceramics. Because of low E c, large P r and the MPB, the ceramics with x = 0–0.02 and y = 0.06 exhibit the optimum piezoelectric properties: d 33 = 155–159 pC/N and k p = 28.8–36.7 % . The temperature dependences of dielectric properties of the ceramics show relaxor-like behaviors. The ferroelectric properties at different temperature suggest that the ceramics may contain both the polar and non-polar regions near/above T d.