Mixtures of iron and anatase TiO2 by mechanical alloying

Fe-doped Fe-doped TiO2 powders were obtained by mechanical alloying. The starting materials were anatase TiO2 and metallic iron (alpha-Fe) or hematic (alpha-Fe2O3). The influence of different milling conditions such as: ball to powder weight ratio, milling time, rotation velocity of supporting disc, and dopant concentration on the structural and magnetic properties were investigated. All experiments were performed in atmospheric conditions. The milled powders were characterized by X-ray diffraction (XRD) using Rietveld refinement and room temperature Mossbauer spectrometry. The XRD patterns of all samples show the coexistence of both anatase and rutile phases and also the high-pressure srilankite phase. Mossbauer spectra reveal the presence of Fe2+ and Fe3+ states in Fe-doped TiO2 as well as alpha-Fe of alpha-Fe2O3 in samples obtained from metallic iron or hematite, respectively. The Fe3+ contribution could be attributed to Fe incorporated in the TiO2 structure and the Fe2+ can be probably assigned to surface ferrous ions in the TiO2. (C) 2008 Elsevier Ltd. All rights reserved.