Dielectric behaviour of porcelain in relation to constitution

The dielectric properties of porcelain bodies prepared with and without the incorporation of mineralisers were investigated at different frequencies (1–10 MHz) and room temperature (25°C). The phase compositions and microstructures of the porcelain bodies were also determined. The influence of concentrations of mullite, quartz, cristobalite and glass as well as size of mullite crystals and the asymmetry of mullite crystal size distribution on dielectric constant, tanδ and loss factor were examined. The results suggested that frequency of the order of 106 Hz had almost no effect on the dielectric constant but influenced the loss factor substantially. Multiple regression equations connecting loss factor with the constitutional parameters of porcelain bodies were developed to calculate loss factor and the calculated and experimental values were compared.