Synthesis of (Bi0.5Na0.5)TiO3 nanocrystalline powders by stearic acid gel method

Bismuth sodium titanate (Na0.5Bi0.5)TiO3 (NBT), is considered to be an excellent candidate for a key material of lead-free piezoelectric ceramics. In this study, we propose a stearic acid gel method for the preparation of nanocrystalline single phase NBT powder at relatively low treatment-temperature. Infrared (IR) spectroscopy, differential thermal analysis (DTA), thermogravimetric analysis (TG) and X-ray diffraction (XRD) were used to characterize the process of crystallization. The particle size and morphology of the calcined powders were examined by TEM. It shows that pure single phase NBT powders could be obtained at 700 °C for 1 h, and the particle size is about 20 nm. With an increase in the calcination temperature, crystallite size increased. The powders were further pressed into disk and sintered at 1120 °C for 2 h in air, and its density and microstructure were compared with traditionally prepared samples.