Effects of KOH/BaTi and Ba/Ti ratios on synthesis of BaTiO3 powder by coprecipitation/hydrothermal reaction

BaTiO3 powders were synthesized by coprecipitation and by the hydrothermal reaction using barium acetate and acylated titanium isopropoxide as starting materials (KOH/BaTi molar ratios: 6:20, Ba/Ti molar ratios: 1.0:1.8). An increase in the Ba/Ti ratio of starting materials was found to give a lower degree of agglomeration in synthesized powders, presumably due to the enhanced adsorption of compounds like barium acetate into titanium-based complexes. A high Ba/Ti ratio of starting materials was found to be more favorable for the formation of stoichiometric BaTiO3. The higher the ratio of KOH to Ba and Ti precursor, the smaller the sizes of crystalline BaTiO3 powders synthesized. When the KOH/BaTi ratio was higher than 13, crystalline BaTiO3 powders were synthesized without subsequent hydrothermal reaction.