Hydrothermal Synthesis and Dielectric Properties of Tetragonal BaTiO3

TLDR: In this article, the tetragonal content of barium titanates was quantified from differential scanning calorimetry by following the endothermic Curie transition around 130{degrees}C and reached as high as 37-39% for the materials made with the barium halides.

Abstract: Hydrothermal synthesis of barium titanate (BaTiO{sub 3}) at 240{degrees}C using different barium salts as starting reactants is examined. It is found that halide salts (I{sup {minus}}, Br{sup {minus}}, Cl{sup {minus}}) result in the highest tetragonal content, followed by acetate, nitrate, and hydroxide salts. The tetragonal content was quantified from differential scanning calorimetry by following the endothermic Curie transition around 130{degrees}C and reached as high as 37-39% for the materials made with the barium halides. The particle sizes ranged from 0.15 to 0.37 {mu}m, as estimated by scanning electron microscopy. Sintering and dielectric properties of the barium titanates synthesized from different barium sources were examined. BaTiO{sub 3} made from the chloride salt sintered with high densities at 1250{degrees}C with grain sizes of 1-5 {mu}m and a room-temperature dielectric constant (1 kHz) of 2960. 35 refs., 10 figs., 1 tab.