Barium titanate and barium orthotitanate powders through an ethylene glycol polymerization route

Nano-size and pure barium titanate and barium orthotitanate powders were synthesized by simple, mixed-oxide, ceramic processing using ethylene glycol. Barium nitrate and titanium isopropoxide were directly dissolved in ethylene glycol in stoichiometric proportions. The organic/inorganic precursors were crystallized to tetragonal barium titanate and monoclinic barium orthotitanate, after calcining at 700 °C for 1 h and at 1200 °C for 1 h, respectively. A dense barium titanate microstructure which had a nano-scale grain size was obtained by sintering at 1200 °C for 2 h. In barium orthotitanate, a phase transformation from orthorhombic to monoclinic symmetry occurred. The transformation temperature and volume change were determined by dilatometry. The high temperature orthorhombic phase was retained down to room temperature by addition of at least 6 wt% MgO stabilizer.