2000 Volume 26 Issue 6 Pages 855-860
In order to design the microstructure of ceramics with desired dielectric property, an estimation method of dielectric constant of ceramics taking into account the characteristics of microstructure of the ceramics is proposed. In the estimation model, the microstructure of ceramics is represented by the assembly of unit cells comprising of grain, pore and grain boundary. The sizes of grain and pore and the thickness of grain boundary in each unit cell were determined exactly according to their size and thickness distributions in a real ceramic. The dielectric constant of the assembly can be calculated on the basis of equivalent circuit theory.
The estimated values of dielectric constant of ceramic BaTiO3 using the proposed estimation method agree well with experimental ones. The dependence of characteristics of microstructure on the dielectric constant was clarified by the estimation of dielectric constants for the assemblies of unit cells with different characteristics. The microstructure of ceramic BaTiO3 with desired dielectric properties can be designed by using the proposed estimation method.