Fabrication of Fe-TiO2 nano-composite powders by mechanical alloying

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.