The effects of mechanical alloying on the solid state reaction of hematite, Fe2O3 and titanium have been investigated at room temperature. We found that the displacement reaction between a Fe2O3 and a more reactive Ti metal can be induced by mechanical alloying. Fe-TiO2 nano-composites in which TiO2 particles were dispersed in an Fe matrix with nano grain size were obtained by mechanical alloying the mixture of Fe2O3-Ti elemental powders for 30 hrs. The average grain sizes of iron in the Fe-TiO2 nano-composite could be reduced to the 20 nm range as estimated by X-ray diffraction line-width measurements. We also show magnetic evidence for the solid state reduction by mechanical alloying through changes in saturation magnetization and coercivity.

Keywords: nano-composite, mechanical alloying, saturation magnetization