The effects of Bi4Ti3O12 on the microstructure and dielectric properties of Mn-doped BaTiO3 were studied using X-ray diffraction (XRD) and transmission electron microscope (TEM). From XRD analysis and scanning electron microscope (SEM) observations, second phase Bi2Ti2O7 was found when the Bi4Ti3O12 content was more than 4 mol%. The grain size was significantly enhanced with increased Bi4Ti3O12 content. The sintering temperature of Mn-doped BaTiO3-based ceramics could be reduced effectively to 1200 °C by doping them with more than 1 mol% Bi4Ti3O12. TEM results show an obvious core-shell structure with 2 mol% Bi4Ti3O12, which was destroyed when the Bi4Ti3O12 content increased from 2 to 4 mol%. It was found that the Curie temperature was shifted to a higher level and the variation of dielectric constant decreased when Bi4Ti3O12 content increased from 0 to 2 mol%. When the Bi4Ti3O12 content was more than 2 mol%, the Curie temperature decreased due to a change of the core-shell structure and secondary phase Bi2Ti2O7. The variation of dielectric constant as compared with that at room temperature was about -25% at -55 °C and less than ±10% at 150 °C. The stable temperature characteristics of the dielectric constant were caused by the presence of the core-shell grain structure. Due to the "clockwise effect", ceramic materials have great potential as EIA X8R-type multilayer ceramic capacitors.
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry