Fabrication And Research On (Ba, Sr, Ca) TiO₃ Based Ceramics

The influences of CeO₂, Y₂O₃, Dy₂O₃ and technical parameters on microstructure and properties were investigated in (Ba_1-x-ySr_xCa_y)TiO₃ (BSCT) ceramics in this paper. Dielectric properties of the samples were measured.The influence of formulate on the dielectric properties of BSCT series ceramic capacitors has been investigated by means of orthogonal design experiments. The major and secondary influencing factors of various factors' levels for the dielectric properties of this ceramics have been obtained. At the same time, the optimum comprehensive properties fomulate G4 has been obtained.The influence of technical parameters, mainly formation press, sintering temperature and time at sintering temperature on dielectric properties were measured. It was showed that suitable parameters can make good dielectric constant, dielectric loss and density value. The optimal parameters for formation press, sintering temperature and time at sintering temperature were attained in this experiment.The influence of the dopants CaTiO₃, CeO₂, Y₂O₃ and Dy₂O₃ on the dielectric properties for ceramic capacitors has also been discussed. Ca²⁺ enter into some Ba2+ location in the crystal lattice, reducing the dielectric constant peak value in the curie point, making curie temperature moving towards low temperature, restraining crystal grain growing up, elevating dielectrical constant. It is found that doping CeO₂ can suppress the grain to grow up validly. And a bit of doping CeO₂ can lower the dielectric losses of this kind of material. It was found that a suitable mount of Y₂O₃ can increase theεr and decrease the tgδ. And a bit of doping Y₂O₃ can sharply increase the breakdown voltage. Doping small rare earth oxide Dy₂O₃ can keep back the growth of crystal grain, producing close grain effect, making curie summit in entire work temperature range scatter and spread, get higher dielectric constant and good capacity temperature property, raising the comperssion strength of BSCT ceramic substantially. The multiple dopants CeO₂, Y₂O₃ and Dy₂O₃ can clearly improve the dielectric properties of the ceramic based on BSCT capacitors.