Study on effective dielectric properties of silicon carbide composites

Abstract

In order to accurately predict the variation rule of the effective permittivity and component content of silicon carbide (SiC) composites, the dielectric constants of SiC nano-particulate and its composites have been investigated by experiments and theoretical calculation. Based on the measured relative effective permittivity of samples with different SiC concentration, a calculation method for effective permittivity was established by modifying effective medium formula and Debye model. By the proposed formulas, the intrinsic permittivity of SiC versus frequency was revealed. The effective permittivity of SiC composites as a function of filling content and frequency was also explored. The relative deviation between the theoretical values and the experimental data was less than 5%. The frequency dispersion characteristic of the dielectric parameters of the component as well as the effect of the fillers on the depolarization field of the composite system was fully taken into consideration during the effective permittivity model establishing. Therefore the proposed effective permittivity model should be suitable for both low-filling and high-filling concentration systems.