Complex permittivity and microwave heating behavior of rod-shaped SiC and oxide (SiO2, Al2O3) mixtures

Permittivity measurement and microwave heating characteristics of rod-shaped SiC (fragmented SiC fiber) mixed with SiO2 or Al2O3 were investigated, comparing with the mixtures of other two kinds of SiC materials. Rod-shaped SiC mixtures had larger permittivity (both real and especially imaginary parts) than the other SiC mixtures, and a broad peak of loss factor (epsilon(r)'') appeared around 1 GHz. Effective permittivity of mixtures was not successfully fitted by Maxwell-Garnett mixing law to the rod-shaped SiC mixtures but well fitted to other kinds of SiC mixtures. The microwave heating ability of rod-shaped SiC mixtures were much superior to that of other SiC mixtures, as expected from the larger loss factors. However, differences were observed between the mixture of rod-shaped SiC with SiO2 and with gamma-Al2O3 in heating behavior and in the mixture permittivity. Interactions of the rod SiC are considered different between SiO2 and gamma-Al2O3 and influenced the experimental heating data.