Nanoscaled BaTiO3 powders with a large surface area synthesized by precipitation from aqueous solutions: Preparation, characterization and sintering

Nanosized BaTiO3 powders with a specific surface area of 60–75 m2/g have been prepared by precipitation of a titanium ester with Ba(OH)2 solution at temperatures less than 100 °C. The effects of the Ba(OH)2 concentration, isopropanol mixing with water as a solvent, the Ba:Ti ratio and surface modifiers on the surface area, the particle size, the crystalline phase, the agglomeration and aggregation degree of the synthesized powders as well as dielectric properties of sintered pellets have been investigated. The properties of the obtained powders have been characterized with XRD, BET, TG-DTA, ICP-AES, HRTEM and dilatometer. A high concentration of Ba(OH)2 can increase the agglomeration and aggregation degree of the particles while the addition of isopropanol in water is beneficial for lowering it. To obtain stoichiometrical barium titanate, the ratio of Ba:Ti should be 1.1. The leaching of barium ions during processing can be limited by washing the powder with ammonia solution at pH10.2. A BaTiO3 ceramic (95.8% of the theoretic density) has been fabricated by sintering the powders at 1250 °C for 2 h.