Effects of nano-sized BiFeO sub(3) addition on the properties of high piezoelectric response (1 - x)Bi sub(0.5)Na sub(0.5)TiO sub(3)-xBi sub(0. 5)K sub(0.5)TiO sub(3) ceramics

The role of BiFeO sub(3) addition on the crystal structure, microstructure, and the electrical and electromechanical properties of high-sensitivity Bi sub(0.5)Na sub(0.5)TiO sub(3)-Bi sub(0.5K) sub(0).5iO sub(3) ferroelectric ceramics for compositions at the morphotropic phase boundary (MPB) is investigated. A perovskite solid solution from nano-sized BiFeO sub(3) and Bi sub(0.5)Na sub(0.5)TiO sub(3)-Bi sub(0.5K) sub(0).5iO sub(3) powders is obtained, in which the persistence of a MPB in the ternary system is demonstrated. The structural characterization, along with the electrical properties, indicates the stabilization of intermediate domain configurations, associated with a decrease of the temperature for the development of the ferroelectric long-range order. As a consequence, high phase-change electromechanical response is found for certain small BiFeO sub(3) additions. This result is very promising for the processing of textured ceramics taking advantage of the decomposition behaviour of BiFeO sub(3). Ceramic texturing is demonstrated, a key technology for developing lead-free piezoelectrics that can replace Pb(Zr,Ti)O sub(3).