Abstract
Barium Titanate (BaTiO3) is widely used in the electric industries, especially in multilayer capacitors due to its high dielectric constant. It is produced conventionally by the solid state reaction of BaCO3 with TiO2 at temperatures above 900°C. This method, however, leads to the production of large BaTiO3 particles with uncontrolled and irregular morphologies, which can limit the electrical properties of the resulting sintered ceramics. By contrast, hydrothermal synthesis has been shown to be a viable route for the production of barium titanate and can be used to produce fine particles with controlled, spherical morphology, a narrow size distribution, and of high purity. Such particles are very much suitable for use in modern green fabrication techniques. Furthermore, the particles can be sintered at lower temperature than conventional method. In this study, a composite powder consisted of barium titanate fine particles and metal particles were synthesized hydrothermally from barium hydroxide and titanium tetraisopropoxide with platinum chloride as well as with silver nitrate. The mean size of barium titanate particles ranged from 0.1 µm to 0.8 µm, depending on the hydrothermal conditions. On the other hand, the mean size of metal particles ranged from 10 nm to 0.3 µm. The dependence of the addition of second metal particles, modifier as well as sintering temperature on the microstructures and dielectric properties of the sintered ceramics has also been investigated.
