Efeito do dopante Ba sobre as propriedades estruturais e microestruturais de ceramicas Bi0.5Na0.5TiO3

Recently, Bi0,5Na0,5TiO3 (BNT) based ceramics has been widely studied as one promising material lead-free for piezoelectric applications. The Ba addition in BNT ((Bi0,5Na0,5)1-xBaxTiO3 - BNT-xBT) has attracted considerable attention due to the existence of a rhombohedral-tetragonal morphotropic phase boundary (MPB) near x = 0.06, where it shows maximized piezoelectric properties. In this study, BNT-XBT ceramics near the MPB (0.05 = x = 0.07), were prepared by solid-state reaction method. The effect of Ba doping on structure and microstructure of the BNT-xBT ceramics was investigated. The X-ray diffraction results show MPB for 0.06 = x <0.07. Raman spectroscopy suggests tetragonal symmetry, wich presence of the band at 300 cm-1 for composition x = 0.07, confirming the presence of the MPB region below this composition. Scanning electron microscopy images indicate apparent decrease of the grain size with increasing Ba concentration.