Low-temperature sintering of BaTiO3 powders prepared by a hydrothermal process with ball milling system

In this work, a hydrothermal process with ball milling system was developed to produce nanosized BaTiO3 powders with low-temperature sintering capability. By using this apparatus, it was possible to synthesize nanosized BaTiO3 powders from Ba(OH)2 and titanium alkoxides at 100 °C after 2 h. The primary particle size was determined to be about 20 nm. Moreover, nanosized BaTiO3 particles were uniformly agglomerated to about 150 nm. The green bodies prepared from these powders were densified above 95% at 900 °C, which is fairly lower than the ordinary sintering temperature. The densification was about 60% at 900 °C in the green bodies fabricated from powders synthesized by the hydrothermal reaction without ball milling system. The sinterability was found higher for the BaTiO3 powders synthesized by ball milling-assisted hydrothermal process. The characterization of the synthesized powders and the sintered compacts was carried out by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. For the electrical properties, room temperature dielectric constants as high as 4000 were measured.