Synthesis of fine Ca-doped BaTiO3 powders by solid-state reaction method—Part I: Mechanical activation of starting materials

摘要

Fine (Ba0.98Ca0.02)1.002TiO3 powders for high capacitance multilayer ceramic capacitors (MLCCs) application were synthesized by solid state reaction method. The effects of mechanochemical activation using high energy milling and the starting materials properties on the reaction temperature and on the final powder properties were investigated. Previous heavy milling of BaCO3 and the adoption of fine, anatase-rich TiO2 phase were effective in decreasing the reaction temperature and in increasing the tetragonality (=c/a). BaCaTiO3 powders with a tetragonality of 1.0097, an average particle size of 213 ± 43 nm and a specific surface area of 6.30 m2/g were acquired after heat treatment at 985 °C for 2 h. MLCCs utilizing this developed powder showed superior dielectric and temperature characteristics to those with conventional, Ca-free BaTiO3 powder.