Influence of Preparation Conditions on Final Dielectric Properties of Pure and Ca-Doped BaTiO3 Ceramics

Improvement of dielectric properties of commonly used electroceramic materials plays an important role in the development of modern electronics. This paper has described the preparations and properties of lead-free BaTiO3-based ceramics obtained from mechanochemically synthesized powder. Ba1-xCaxTiO3 powders with different calcium contents (0 <= x <= 0.20) have been successfully obtained by mechanochemical synthesis directly at room temperature (without any additional thermal treatment). Mechanochemically triggered reaction, leading to the formation of perovskite phase, has been monitored by XRD at different stages. Pure and Ca-doped barium titanate powders have been consolidated (1) by pressing and subsequently conventional sintering or (2) by hot pressing. The influence of the sintering method on the dielectric properties of the ceramics has been investigated by dielectric spectroscopy in the temperature range from 25 to 180 degrees C. Both the sintering method and the doping with Ca have a strong effect on the dielectric permittivity and dielectric losses of barium titanate ceramics.