Effects of dry grinding of powder mixture on formation of cordierite in sintered body and its mechanical properties

Dry grinding a mixture composed of kaolinite, talc, and aluminum hydroxide was conducted using a tumbling ball mill to investigate its effect on forma tion of cordierite in a sintered body prepared from the ground product and its mechanical and thermal properties. The grinding enables us to induce st ructural changes in the raw materials, namely into amorphous state with goo d homogenization. Prolonged grinding of about 192 h leads to the formation of single-phase alpha -cordierite from the ground product at relatively low sintering temperature. Grinding for 192 h and sintering at 1573 K allows u s to produce dense cr-cordierite in the sintered body, having high Vickers hardness (700 Hv) and a low linear thermal expansion coefficient of 0.6 x 1 0(-6)/K (298-1173 K),