Preparation of nano-sized BaTiO3 particle by citric acid-assisted spray pyrolysis

Nano-sized BaTiO3 particles were prepared by citric acid (CA)-assisted spray pyrolysis. It was found that controlling the spray solution with an organic additive made great differences in the structure and morphology of BaTiO3 particles during the calcination. High agglomerated particles of irregular shape were produced after the calcination at 1050 °C when they were prepared from the nitrate solution without organic additive. In contrast, coarse aggregates consisting of nano-sized BaTiO3 primary crystallites were obtained when we used the nitrate solution containing an organic additive (citric acid, CA). The coarse aggregates were successfully disintegrated to nano-sized BaTiO3 particles with narrow particle size distribution after a simple ball-milling process. The use of CA additive also affected the crystallographic behavior of the BaTiO3 nanoparticles. The CA additive prevented phase separation of barium and produced phase-pure BaTiO3 particles at the as-prepared state and enhanced the phase transformability of metastable cubic phase to the tetragonal one during calcination. Consequently, BaTiO3 nanoparticles of about 150 nm with good tetragonality were successfully obtained by simple ball milling the coarse aggregates that were prepared from the CA-assisted spray pyrolysis and calcination at 1050 °C.