Formation of BaTiO ₃ from BaCO ₃ and TiO ₂ in Air and in CO ₂

Abstract

The formation of BaTiO 3 from equimolar BaCO 3 and TiO 2 (rutile) mixtures was studied in air and in CO 2 . A small amount of BaTiO 3 is formed first directly from BaCO 3 and TiO 2 at the surface of contact. From then on it is a diffusion‐controlled reaction, and both BaTiO 3 and Ba 2 TiO 4 are produced, with Ba 2 TiO 4 being formed in much larger amounts. In 1 atmosphere of CO 2 , the intermediate Ba 2 TiO 4 was suppressed up to a temperature of about 1100°C. in agreement with thermodynamic calculations. Ba 2 TiO 4 reacts fast with 1 atmosphere of CO 2 below about 1100°C. to produce BaTiO 3 and BaCO 3