METAL-ORGANIC RESIN DERIVED BARIUM-TITANATE .1. FORMATION OF BARIUM TITANIUM OXYCARBONATE INTERMEDIATE

Crystallization of BaTiO3 from an X-ray amorphous, metal organic precursor was investigated by comparing samples heated in O2, air, argon, and CO2. It is evident that an intermediate barium titanium oxycarbonate phase forms between 500-degrees and 620-degrees-C and that BaTiO3 forms directly by the endothermic decomposition of this phase between 635-degrees and 700-degrees-C. From thermodynamic calculations, thermal analysis, X-ray diffraction, and Raman spectroscopy, it is concluded that the intermediate oxycarbonate is a highly disordered, metastable, and weakly crystalline phase with a stoichiometry close to Ba2Ti2O5CO3.