Bi nonstoichiometry and composition engineering in (1-x)Bi1+yFeO3+3y/2 - xBaTiO(3) ceramics

摘要

Bi is easily evaporated during the preparation of BiFeO3, and moreover its phase structure and electrical properties can also be modified by doping BaTiO3. In this work, the effects of Bi nonstoichiometry as well as BaTiO3 on the phase purity, microstructure, and electrical properties of (1 - x)Bi1+yFeO3+3y/2 - xBaTiO(3) (0.25 <= x <= 0.35 and -0.1 <= y <= 0.25) ceramics were studied. A rhombohedral-pseudocubic (R-C) phase boundary was formed in the ceramics with a wide composition range of x = 0.30 and -0.05 <= y <= 0.15, leading to an enhanced piezoelectricity (d(33) similar to 180 pC/N). In addition, one can find that dense microstructure as well as the improvement of Curie temperature (T-C similar to 506 degrees C) and thermal stability of piezoelectricity (T-a = 400 degrees C) can be achieved in the ceramics with excess Bi (x = 0.30, y = 0.05) with respect to the ones with Bi deficiency. We expect that the investigation on Bi nonstoichiometry and the addition of BaTiO3 will point out an effective method to fabricate high-performance BFO-based ceramics.