Influence of one activated component on the sintering process of three phase system

Abstract

According to its low temperature thermal expansion coefficient, low dielectric constant, also good mechanical properties, cordierite, 2MgO×2Al2O3×5SiO2, represents a very attractive hightemperature ceramic material. In this study, cordierite was prepared by solid state reaction of the MgO, Al2O3 and SiO2 mixture. One of the components from the mixture, SiO2, was mechanically activated in a high energy ball mill during 5 and 10 minutes. The applied pressure before the sintering process was 2 t/cm2. Sintering process of mixtures containing non-activated and activated SiO2 powder was performed at 1350 oC for 4h in the air atmosphere. The phase composition of starting oxides and sintered samples was analyzed by the X-ray diffraction method. Particle size analysis was performed to investigate the differences between starting components. Scanning electron microscopy was done to analyze the microstructure of both components and sintered samples. This paper investigates the influence of one mechanically activated SiO2 component on the densities of green bodies as well as on the sintered samples, along with electrical properties of cordierite ceramics.