Nanocomposite formation in haematite-Mg, Ti system induced by high-energy ball milling

Reactant materials of haematite and Mg, Ti powders have been milled, where pure metals are used as reducing agent. It is found that nanocomposite powders in which MgO and TiO2 are dispersed in alpha-Fe matrix with nano-sized grains are obtained by MA of Fe2O3 with Mg and Ti for 30 min and 5 hours, respectively. It is suggested that the shorter MA time for the nanocomposite formation in Fe2O3-Mg is due to a larger negative heat associated with the chemical reduction of reactant materials. X-ray diffraction results show that the average grain size of alpha-Fe in alpha-Fe/TiO2 nanocomposite powders is in the range of 40 nm. From magnetic measurement, we can also obtain indirect information about the details of the solid-state reduction process during MA.