Mechanochemical activation of titanium-magnetite mixtures

CRISTÓBAL, A.A.; PORTO LÓPEZ, J.M.; AGLIETTI, E.F.; SIVES, F.R.; MERCADER, R.C.

Rio de Janeiro, Brasil

Conferencia; Tenth Latin American Conference on the Applications of the Mössbauer Effect (LACAME 2006); 2006

Mechanochemical Activation of Titanium-Magnetite Mixtures A. A. Crist¶obal, J. M. Porto L¶opez Instituto de Investigaciones en Ciencia y Tecnolog¶³a de Materiales, INTEMA, Divisi¶on Cer¶amicos, Av. J. B. Justo4302, B7608FDQ Mar del Plata, Argentina E. F. Aglietti Centro de Tecnolog¶³a de Recursos Minerales y Cer¶amica, CETMIC, Camino P. Centenario y 506, 1897 M. B. Gonnet, Argentina F. R. Sives, R. C. Mercader Departamento de F¶³sica, IFLP, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C. C. 67, 1900 La Plata, Argentina Mechanochemical processes involving reactions between metals and crystalline oxides are of interest because {in addition to their potential technological applications in structural, magnetic or electric materials through the development of metastable and non-crystalline materials with controlled properties{ they add to the un- derstanding of the natural occurring processes that lead to the formation of minerals and soils. On the other hand, natural series of minerals in the solid solution series between magnetite (Fe3O4) and UlvÄospinel (Fe2Ti04) and their intermediate members, titano-magnetites, also display di®erences in the degree of oxidation and their cation distribution among the spinel structural sites. The controlled studies of how the distribution of cations 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 hyper¯ne behavior, we have set about to study a series of titanium and magnetite mixtures with diverse activation conditions. We have studied the development of new phases other than the initial Ti and Fe3O4 ones by x-ray di®raction (XRD), scanning electron microscopy, di®erential thermal analysis, AC susceptometry and MÄossbauer spectrometry. As a result of the mechanochemical activation produced by high-energy ball-milling of the mixtures in Ar at- mosphere at room temperature, the Ti reduces the Fe ions in the Fe3O4 spinel, partly to Fe2+ and partly to metallic Fe. By MÄossbauer spectrometry, magnetic measurements and XRD, we have been able to follow the evolution of the changes in the contents of the main phases, ®-Fe, °-Fe, Ilmenite and UlvÄospinel. The values obtained by the diverse techniques are discussed according to the di®erent materials properties on which the techniques are based.3O4) and UlvÄospinel (Fe2Ti04) and their intermediate members, titano-magnetites, also display di®erences in the degree of oxidation and their cation distribution among the spinel structural sites. The controlled studies of how the distribution of cations 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 hyper¯ne behavior, we have set about to study a series of titanium and magnetite mixtures with diverse activation conditions. We have studied the development of new phases other than the initial Ti and Fe3O4 ones by x-ray di®raction (XRD), scanning electron microscopy, di®erential thermal analysis, AC susceptometry and MÄossbauer spectrometry. As a result of the mechanochemical activation produced by high-energy ball-milling of the mixtures in Ar at- mosphere at room temperature, the Ti reduces the Fe ions in the Fe3O4 spinel, partly to Fe2+ and partly to metallic Fe. By MÄossbauer spectrometry, magnetic measurements and XRD, we have been able to follow the evolution of the changes in the contents of the main phases, ®-Fe, °-Fe, Ilmenite and UlvÄospinel. The values obtained by the diverse techniques are discussed according to the di®erent materials properties on which the techniques are based.3O4 ones by x-ray di®raction (XRD), scanning electron microscopy, di®erential thermal analysis, AC susceptometry and MÄossbauer spectrometry. As a result of the mechanochemical activation produced by high-energy ball-milling of the mixtures in Ar at- mosphere at room temperature, the Ti reduces the Fe ions in the Fe3O4 spinel, partly to Fe2+ and partly to metallic Fe. By MÄossbauer spectrometry, magnetic measurements and XRD, we have been able to follow the evolution of the changes in the contents of the main phases, ®-Fe, °-Fe, Ilmenite and UlvÄospinel. The values obtained by the diverse techniques are discussed according to the di®erent materials properties on which the techniques are based.3O4 spinel, partly to Fe2+ and partly to metallic Fe. By MÄossbauer spectrometry, magnetic measurements and XRD, we have been able to follow the evolution of the changes in the contents of the main phases, ®-Fe, °-Fe, Ilmenite and UlvÄospinel. The values obtained by the diverse techniques are discussed according to the di®erent materials properties on which the techniques are based.®-Fe, °-Fe, Ilmenite and UlvÄospinel. The values obtained by the diverse techniques are discussed according to the di®erent materials properties on which the techniques are based.