Synthesis reaction of metatitanate BaTiO₃

Abstract

Thermogravimetric and X-ray diffraction analysis of the reaction mixture, during the synthesis of barium metatitanate BaTiO₃ from BaCO₃ and TiO₂ allowed clarification of the transformation time and the role of the reaction environment: in air, the occurrence of BaTiO₃ is in competition with that of orthotitanate Ba₂TiO₄. The latter forms between 25 and 95% of the transformation of the initial mixture by reaction between BaCO₃ and BaTiO₃. Under vacuum, metatitanate is not detected before 70% of transformation of the initial mixture. The orthotitanate occurs alone, oxide BaO produced by the decomposition of the carbonate and replaces it in the reaction syntheses. In CO₂, the synthesis of BaTiO₃ competes with the formation of a phase other than Ba₂TiO₄ but whose behaviour during calcination is comparable to that of the orthotitanate.