Influence of mechanochemical activation on sintering of cordierite ceramics with the presence of Bi2O3 as a functional additive

Abstract

According to its exceptional electrical characteristics, such as low temperature expansion coefficient, low dielectric constant and good mechanical properties, cordierite, 2MgO⋅2Al2O3⋅5SiO2, represents very attractive ceramic material in the field of high temperatures. In order to accelerate the process of sintering, 1 mass% Bi2O3 has been added to starting mixtures. Liquid phase sintering caused by presence of bismuth-oxide leads to lowering temperature of cordierite formation. Mechanical activation of starting mixtures (0-56 minutes in vibro-mill) additionally leads to lowering sintering temperatures. Process of sintering was performed at 1200, 1300 and 1400 oC, for 2h. BET and PSA were employed in order to follow the changes in specific surface area and particle size of mechanically treated powders. Phase composition of starting powders and sintered materials was analyzed by X-ray diffraction method. Moreover, SEM analysis was used for analysis of powders morphology and sintered pallets microstructure.