J. Phys. IV France 07 (1997) C1-615-C1-616
IR Studies of the Phase Transformation of Fe2O3 → Fe3O4by Magnetomechanical ActivationI. Jacyna-Onyszkiewicz1, M. Grunwald-Wyspianska2 and W.A. Kaczmarek3
1 Institute of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland
2 Department of Chemistry, A. Mickiewicz University, Grunwaldzka 6, 60-780 Poznan, Poland
3 Institute of Advanced Studies, Research School of Physical Sciences and Engineering, Australian National University, Canberra, A.C.T. 0200, Australia
The phase transformation of hematite αFe2O3 into magnetite Fe3O4 during wet milling in vacuum as a result of mechanochemical process has been investigated by infrared spectroscopy. The FTIR spectra were recorded in the wavenumber range kom 400 to 4000 cm-1. Two very strong bands were generally observed : one in the range 557-577cm-1 with shoulders in 632-693 cm-1, the other at about 475 cm-1. The most important feature is a very strong dependence of the intensities of the main absorption bands on the milling time of the sample. In addition, there was a broad band in the 3000-3700 cm-1 region related to the appearance of a certain number of OH groups in the spinel lattice. The results are discussed assuming the theoretically indicated active IR modes for ferites. A little disorded was interpreted as generated by ball milling and no traces of amorphization were observed.
© EDP Sciences 1997