Effect of SiO_2 addition on the dielectric properties and microstructure of BaTiO_3-based ceramics in reducing sintering

摘要

The effect of SiO2 doping on the sintering behavior,microstructure,and dielectric properties of BaTiO3-based ceramics has been investigated. Silica was added to the BaTiO3-based powder prepared by the solid state method with 0.075mol%,0.15mol%,and 0.3mol%,respectively. The SiO2-doped BaTiO3-based ceramic with high density and uniform grain size were obtained,which were sintered in reducing atmosphere. A scanning electron microscope,X-ray diffraction,and LCR meter were used to determine the microstructure as well as the dielectric properties. SiO2 can form a liquid phase belonging to the ternary system of BaO-TiO2-SiO2,leading to the formation of BaTiO3 ceramics with high density at a lower sintering temperature. The SiO2-doped BaTiO3-based ceramics can be sintered to a theoretical density higher than 95% at 1220°C with a soaking time of 2 h. The dielectric constants of the sample with 0.15mol% SiO2 addition sintered at 1220°C is about 9000. Doping with a small amount of silica can improve the sintering and dielectric properties of BaTiO3-based ceramics.