Relaxation phase transition and ferroelectric properties of Na0.5Bi0.5TiO3 -BaTiONa0.5Bi0.5TiO3 system lead-free piezoceramics

Relaxation property, phase transition and ferroelectric properties of (1-x)Na0.5Bi0.5TiO3 - xBaTiO3 lead-free piezoceramics system were investigated. X-ray diffraction results indicate that the morphotropic phase boundary between rhombo-hedral and tetragonal exists in the range of 0.06 ≤ x ≤ 0.10. The temperature dependence of dielectric constant εr indicates that the ceramics with the composition range of x ≥ 0.10 exhibit relaxation properties at the temperature higher than 200°C. The double hysteresis loops show that the anti-ferroelectric phase exists in the heating process of ceramics with defined composition. The ferroelectric properties of samples were studied. It is found that the lowest value of coercive field is obtained for the specimen with the composition of x = 0.10.