Microstructure and Dielectric Properties of Ceramic Bodies Containing Um Risha Syenite Doped with Coflux Oxides

Abstract

This paper reported the effect of the addition of Um Risha quartz alkali feldspar syenite from Egypt, which containing a high amount of Fe2O3 and alkaline oxides mainly K2O and Na2O used as a flux material, on the densification properties, sinterability, crystalline phases, microstructure and dielectrical properties of ceramic body composed of 50 Um Risha quartz alkali feldspar syenite, 40 clay and 10 alumina, weight % doped with CuO, MnO2 and ZnO used as coflux oxides with content 2, 3 and 5 weight %. The physical properties in terms of linear shrinkage, bulk density, water absorption and apparent porosity of the fired ceramic bodies were investigated at different firing temperatures to determine their maturing temperatures. The addition of CuO and MnO2 reduce the maturing temperature but the addition of ZnO addition has not any effect on the maturing temperature of the fired ceramic bodies. The formed phases in the base sample were quartz, cristobalite, corundum, mullite at 1100 °C. As well as Copper aluminate CuAl2O4, Manganese aluminate Mn2AlO4 and Zinc aluminate ZnAl2O4 were formed due to the addition of CuO, MnO2 and ZnO. XRD and SEM analyses were used to examine the development of the phases under consideration. It was observed that the addition of CuO, MnO2 and ZnO to the base sample increase the dielectric constant, dielectric loss and decrease the resistivity at frequency ranges from 200 Hz to 50 KHz at room temperature.