Barium titanate sols prepared by a diol-based sol-gel route

A diol-based sol-gel route for preparing barium titanate precursor sols has been developed. The sols were prepared using 1,3 propanediol, barium acetate, and titanium isopropoxide, modified by acetylacetonate. The decomposition behavior of samples of gel, dried at 120 °C, was studied by GC-MS, TGA and DSC; phase formation was investigated by XRD and FTIR techniques. From the XRD results for calcined gel powders, crystalline barium titanate began to form at ∼600 °C. FTIR spectra showed two absorption bands at 538 cm−1 and 400 cm−1 in samples calcined at 600 °C; these peaks are assigned to barium titanate, in accord with the XRD results. There was also FTIR evidence of a carbonate phase, which persisted until a calcination temperature of ∼1000 °C. The sols have been kept in a closed container for ∼6 months without any evidence of precipitation or gel formation.