Effect of CO₂ Partial Pressure on Morphology and Growth of Particle of BaTiO₃ in Solid State Reaction Process

Abstract

BaTiO₃ (BT) was synthesized by the solid state reaction of an almost equimolar mixture of BaCO₃ and TiO₂ in various atmospheres. The rate of reaction decreased as the CO₂ partial pressure increased. There observed no Ba₂TiO₄ irrespective of the CO₂ partial pressure in the whole temperature range studied. The morphology of BT powder calcined at 1035°C in air was spherical. However, it was angular and the particle growth was inhibited when calcined at 1035°C in the atmosphere with above 30vol% of CO₂ partial pressure. Furthermore, the amount of the remained BaCO₃ during the solid state reaction for angular BT was larger than that for spherical one from the X-ray diffraction analysis. It was found that BaCO₃, of which decomposition was suppressed by the high CO₂ partial pressure, had a considerable influence on the reaction rate, morphology of the particle, and the particle growth in the solid state synthesis of BT.