Influence of thermal treatment on morphology and dielectric properties of barium calcium titanate Ba0.7Ca0.3TiO3 ceramics prepared from mechanochemically synthesized powders

Piezoelectric lead-free materials have attracted much attention with the increasing demand for environmental protection and policies. Mechanochemistry is radically different from the traditional way of dissolving, heating and... [ view full abstract ]

Piezoelectric lead-free materials have attracted much attention with the increasing demand for environmental protection and policies. Mechanochemistry is radically different from the traditional way of dissolving, heating and stirring chemicals in a solution. Because it eliminates the need for many solvents and calcinations, mechanochemistry could help make many industry processes more environmentally friendly. Barium calcium titanium (Ba_1−xCa_xTiO₃ or BCT) is an important ferroelectric and antiferroelectric material, so many efforts have been devoted to study the dielectric properties of barium titanium based materials obtained by various technologies.
In this work lead-free barium calcium-titanate Ba_0.7Ca_0.3TiO₃ powders were obtained by mechanochemical synthesis in shaker type SPEX 8000 Mixer Mill. The perovskite phase formation, confirmed by X-ray powder diffraction, has taken place directly during high energy milling. The obtained powders were used for the preparations of ceramic samples. The influence of sintering conditions on ceramic morphology was investigation by scanning electron microscopy. The ceramic properties were investigated using dielectric spectroscopy. The dielectric measurements as well as the microstructure investigations have revealed the strong correlation between the properties of ceramics and sintering temperature.

Acknowledgements

The work was partially financed by Polish Ministry of Science and Higher Education within statutory activity.

Keywords: BCT ceramics, X-ray diffraction and SEM analysis, measurements of dielectric permittivity, Ca²⁺ doping