Phase structure and piezoelectric properties of NBT-KBT-BT ceramics prepared by sol-gel flame synthetic approach

Sol-gel flame synthetic approach was used to produce powders and the resultant ceramics of (Na0.5Bi0.5)TiO3-(K0.5Bi0.5)TiO3-BaTiO3 (NBT-KBT-BT) with different compositions. Detailed analysis of polarization-electric field (P-E) loops and strain-electric field (S-E) curves reveals that a tetragonal antiferroelectric-like phase exists at room temperature with a suitable composition. Because of the morphotropic phase boundary (MPB) behavior, the maximum piezoelectric constant d(33) of about 213 pC/N with an electromechanical coupling factor k(p) of about 29% and a remnant polarization P-r of 23.55 mu C/cm(2) were obtained in the 0.90NBT-0.05KBT-0.05BT ceramics. This work provides new insight to further optimized lead-free NBT-KBT-BT piezoelectric ceramics for practical use in different composition ranges at room temperature. (C) 2014 Elsevier B.V. All rights reserved.