Low temperature evolution of crystalline BaTiO3 from alkali-metal free precursor using sol-gel process

Bulk structure and surface texture of BaTiO3 materials synthesized at low temperature using sol-gel technique have been investigated. The materials were produced by the pyrolysis of an xerogel precursor of the tentative formula BaTiO3-x(CH3COO)(2x), which was pre pared using 1:1 molar ratio of barium acetate and titanium oxyacetate solution. The present method avoids using alkali-metal hydroxides (as a hydrolyzing agent), and thus produces an alkali-metal free precursor. The decomposition course of the xerogel at the onset of formation of crystalline BaTiO3 was probed applying thermogravimetry (TG), differential scanning calorimetery (DSC), Fourier-transform infrared spectroscopy (FTIR), and Xray diffraction (XRD) techniques. Results indicated that most of the precursor weight loss occurs below 400 degrees C, with the formation of titania rich intermediates. However, it was not until the temperature reached greater than or equal to 600 degrees C that well crystallized BaTiO3 was produced. The specific surface area and porosity were assessed for BaTiO3 produced at 600-1000 degrees C using N-2 adsorption at liquid N-2 temperature.