IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
artículos
Título:
Structural and magnetic properties of a mechanochemically activated Ti-Fe2O3 solid mixture
Autor/es:
A. CRISTÓBAL; C. P. RAMOS; P. G. BERCOFF; S. CONCONI; E. AGLIETTI; P. M. BOTTA; J. M. PORTO LÓPEZ
Revista:
MATERIALS RESEARCH BULLETIN
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Año: 2010 vol. 45 p. 1984 - 1989
ISSN:
0025-5408
Resumen:
The mechanochemical effects on the reactivity and properties of a
titanium/hematite powder mixture with molar ratio of 1/2 are investigated.
Crystalline-phase structure, composition, hyperfine and magnetic behaviors were
analyzed as a function of activation time by means of X-ray diffraction, scanning
electron microscopy, Mössbauer spectroscopy and vibrating sample magnetometry.
The results showed that at relatively short activation times metallic Ti
reduces part of the ferric ions, yielding a complex product formed mainly by a
mix of two solid solutions Fe3-xTixO4
(titanomagnetites), both with very different x values (0<x<1).
Also metallic iron and superparamagnetic hematite particles were detected by
Mössbauer spectroscopy. As the mechanical treatment extends the composition of
the reactive mixture changes, prevailing in the end the solid solution with
higher x value. In contrast, when these activated samples are thermally treated
the fraction of the solid solution which is richer in Ti diminishes. This fact
produces a significant variation of the saturation magnetization of the
obtained material.