Synthesis and characterization of tetragonal barium titanate powders by an ion-exchange and hydrothermal process

Tetragonal barium titanate (BaTiO₃) powder with a uniform size distribution was successfully prepared by an ion-exchange treatment followed by hydrothermal process, and with a high precursor concentration. Ion-exchange treatment of the bariumtitanium chloride led to the formation of the homogeneous Ba-Ti hydroxide sol. Then, hydrothermal (240^oC for 7 h) led to the preparation of BaTiO₃ powders with a very narrow size distribution (90 ± 3 nm) and a very high tetragonal content (90%), which were confirmed respectively by scanning electron microscopy and differential scanning calorimetry. Further, using the regenerated resin to ion-exchange, the BaTiO₃ yield reached 99%.