Preparation of Ultrafine Barium Titanate Powder by Coprecipitation

This paper investigated the preparation of ultrafine barium titanate powders by us- ing titanium tetrachloride and barium chloride as starting materials and NH4HCO3+NH3.H2O as the precipitant. First of all, a thermodynamic analysis was made in detail to find out opti- mum synthesis conditions. Experiment results show that the Ba/Ti ratio of starting materials, calcination temperature, pH value of solution, have a close effect to the physical and chemical performances of the obtained powders. The best conditions are NH4HCO3/BaCl2·2H2O=1.2; TiCl4/BaCl2.2H2O=1～1.01; reaction time=1h; calacination temperature=920℃ and calcination time 2h. The addition of some dispersants into the reactant system can obviously reduce particle sizes of the product.