Synthesis and characterization of barium strontium titanate nano powders by low temperature ambient pressure sol process

摘要

Crystalline (Ba _x Sr_(1-x) TiO_3) (x = 0, 0.5 0.8 and 1) nanosized powders is synthesized by an ambient pressure and low temperature sol process. The influence of Ba/Sr ratio, temperature, pH and reflux time on the phase formation and morphology of (Ba _x Sr _(1-x) TiO_3) powders is assessed. Amorphous powders are obtained at temperatures lower than 90°C and crystalline, stoichiometric and monophasic Ba _x Sr_(1-x) TiO_3 (x = 0, 0.5, 0.8 and 1), powders are synthesized at 95°C. Under identical preparation conditions, the powder particle size depends on the Ba/Sr ratio. High values of pH decrease the particle size. For reflux times lower than 2 h the particle size decreases with increasing of reflux time, reflecting the dominant role of the nucleation step. For reflux times higher than 2 h the growth step becomes dominant and the particle size increases with the increase of reflux time.