Influence of Mechanical Activation on the Phase Formation in the Synthesis of Cordierite from Talc and Andalusite

Cordierite is known as a leading candidate material for many applications. In this study, mechanical activation assisted synthesis of cordierite using andalusite as a starting material was attempted and phase formation of powder obtained from the heat treatment of talc-andalusite-silica system was investigated. The stoichiometric composition of cordierite (2MgO·2Al2O3·5SiO2) was prepared and ground in planetary ball mill at the rotational speed of 300 and 500 rpm for 0, 30, 60 and 90 min. The powder mixtures were heat treated in air at the temperature ranging from 1150 to 1350°C for 2 hours. Thermal reaction, phase present and microstructure of the starting materials and synthesized products were analyzed by differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. It was found that cordierite phase increased with the grinding time and speed and synthesis temperature. The kinetics of phase formation in this system were also discussed.