Enhancement of Carbothermic Reduction of Al2O3 via Mechanical Milling

The mixture of Al2O3 and graphite with a molar ratio (1:3) were mechanically milled in a planetary ball mill at room temperature using zirconia ball. The mixture was milled for 0.5, 1, 2, 4 and 8 h in air atmosphere. Unmilled and milled mixtures were characterized using a combination of X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), specific surface area analysis (SSA), and thermogravimetry analysis (TGA). TG analysis indicated that the reduction reaction of milled sample occurs at lower temperature compared to the unmilled sample. Mechanical milling of Al2O3-graphite mixtures has led to the following results; size reduction of the Al2O3 crystallite up to similar to 20nm, formation of amorphous graphite and the increase in the surface area of Al2O3