Processing of cordierite based ceramics from alkaline-earth-aluminosilicate glass, kaolin, alumina and magnesite

Microstructural changes, porosity evolution and properties of cordierite based composites have been studied as a function of cordierite–anorthite ratio in modelled ceramic systems. The model systems were composed of alkaline-earth-aluminosilicate glass powder, kaolin, alumina and magnesite. Suitable densification levels of investigated compositions are attained in a narrow temperature range and relatively high residual porosity levels are observed. These features were attributed to the role of the liquid phase during high temperature sintering. Cordierite, anorthite or mixtures of each with mullite are the formed crystalline phases when maximum densification levels are achieved. Their properties are correlated to the processing route and to the composition of sintered materials. Control of the porous structure through manipulation of heating rate was found feasible and easy to implement.