Direct preparation of ultrafine BaTiO₃nanoparticles by chemical vapor synthesis

Ultrafine, crystalline barium titanate (BaTiO₃) nanoparticles were synthesized by chemical vapor synthesis (CVS). Titanium- and Barium-organometallic solid precursors were vaporized using a laser flash evaporator as precursor delivery unit. The process parameters such as precursor ratio, reactor temperature, and reactor length were varied in order to find the optimal conditions to allow the direct synthesis of crystalline particles with the stoichiometric composition. Crystalline, spherical nanoparticles with a size of about 8 nm, free of barium carbonates and with low degree of agglomeration were obtained using a precursor ratio of Ba/Ti = 4, a maximum reactor temperature of 1,700 °C, and a total reactor length of 165 cm. The potential of the CVS process for the synthesis of nanoscaled, impurity-free, and phase-pure BaTiO₃particles in one step is presented. The results demonstrate the capabilities of the CVS method, not only for the preparation of BaTiO₃, but also for many other multi-component systems.