Effect of heating temperature of expandable graphite on amorphization behavior of powder expanded graphite-Fe mixtures by ball-milling

Three expanded graphites, EG1, EG2 and EG3 that were prepared by rapid heating expandable graphite to 600, 800 and 1000 °C, respectively, were ball-milled in a high-energy mill (planetary-type) in an air atmosphere with 16.7% iron powder addition. The X-ray diffraction patterns of the products show that the amorphization process of the powder EG-Fe mixtures during ball-milling is accelerated with increasing the heating temperature of expandable graphite. In addition, amorphous EG-Fe system and Fe3C phase are formed in the ball-milled EG3-Fe. Compared with the amorphization process of EGs without iron addition during ball-milling, the presence of iron restrains the process of EG1 in rate, but it promotes the process of EG3.