CHARACTERIZATION OF A MECHANOCHEMICALLY ACTIVATED TITANIUM-HEMATITE MIXTURE: MÖSSBAUER SPECTROSCOPY STUDY

A. A. CRISTÓBAL; C. P. RAMOS; P. M. BOTTA; E. F. AGLIETTI; C. SARAGOVI; J. M. PORTO LÓPEZ

Buenos Aires

Congreso; At the Frontiers of Condensed Matter IV.; 2008

CNEA

Mechanochemical processes involving reactions between metals and crystalline oxides are of interest because their potential technological applications in structural, magnetic or electric materials. In addition they can contribute to the understanding of the natural occurring processes that lead to the formation of minerals and soils. The controlled studies of how the distribution of cations in the titanomagnetites takes place can help toward building a model for the nature of their magnetism, and, since they are the primary carriers of rock and soil magnetism, are therefore intensively investigated in many experimental and theoretical studies. Toward a better understanding of the thermal, physical-chemical, magnetic and hyperfine behavior, we have considered a series of titanium and hematite mixtures mechanochemically activated during different activation times. We have studied the development of new phases by X-ray diffraction (XRD), scanning electron microscopy, differential thermal analysis and Mössbauer spectroscopy. The evolution from the starting materials affected by different milling times and subsequent annealing show that the Ti reduces the Fe ions in the Fe2O3 lattice, partly to Fe2+ and partly to metallic Fe. All these techniques reveal mainly the formation of a solid solution (formed by ulvospinel and magnetite) and also the appearance of metallic iron.