S. Kumar et al., METAL-ORGANIC RESIN DERIVED BARIUM-TITANATE .1. FORMATION OF BARIUM TITANIUM OXYCARBONATE INTERMEDIATE, Journal of the American Ceramic Society, 76(3), 1993, pp. 617-624
Crystallization of BaTiO3 from an X-ray amorphous, metal organic precu
rsor was investigated by comparing samples heated in O2, air, argon, a
nd CO2. It is evident that an intermediate barium titanium oxycarbonat
e phase forms between 500-degrees and 620-degrees-C and that BaTiO3 fo
rms directly by the endothermic decomposition of this phase between 63
5-degrees and 700-degrees-C. From thermodynamic calculations, thermal
analysis, X-ray diffraction, and Raman spectroscopy, it is concluded t
hat the intermediate oxycarbonate is a highly disordered, metastable,
and weakly crystalline phase with a stoichiometry close to Ba2Ti2O5CO3
.