Piezoelectric Property and Relaxation Phase Transition of Na_(1/2)Bi_(1/2)TiO_3-BaTiO_3 System

For (1-x)Na1/2Bi1/2TiO3-xBaTiO3(x=0.02, 0.04, 0.06, 0.08, 0.10) lead-free ceramic system the morphotropic boundary, piezoelectric property, relaxation property and phase transition were investigated. The piezoelectric ceramics of this system possess large ratios of Kt/Kp and high frequency constants. According to XRD patterns, the morphotropic boundary lies in the composition range of 0.04 x 0.06. The main physical properties of this system can reach extreme values near the morphotropic boundary. The relaxation property of this system was studied by using dielectric constant-temperature curves and thermally stimulated depolarization current (TSDC) curves. Phase transition from ferroelectric to paraelectric phase was also primarily discussed and it was found out that the ceramics within a composition range possess transitional phase region between ferroelectric phase and paraelectric phase.