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A Low Temperature Synthesis of CoFe2O4 Ferrite
|Rodica-Mariana ION 1,2, Dragos-Viorel Brezoi 1|
1. "Valahia" University of Targoviste - Faculty of Materials Science and Engineering, Unirii Avenue, Targoviste 130082, Romania
Low temperature synthesis of such materials has been found to yield to ultrafine particles with unique and unusual particle size by means of chemical stoichiometry reaction. The aim of this work was to prepare ultrafine cobalt ferrite by a wet chemical method. Ammonium oxalate and a solution of hydrazine hydrate were mixed and stired under argon atmosphere at 80 oC to provide amonium oxalate hydrazinate. A satured mixture of cobalt and ferrous chloride solution was added slowly to the amonium oxalate hydrazinate complex to obtain a precipitate of cobalt and ferrous oxalate hydrazinate complex with chemical formula CoFe2∙3N2H4∙6H2O. The precipitate was washed, filtred and dried at 70 oC and then, heated in air at 260 oC for decomposes the precursor and producing a powder of oxide material. This material was analysed after a thermal treatment at 500 oC in air. For characterization, we have used chemical analyses, X-ray diffraction (XRD), UV-Vis absorbance spectroscopy, IR spectroscopy, thermal analyses TG-DTG, Mossbauer spectroscopy, and electron microscopy. The optimum composition of oxalate hydrazinate precursors from the point of view of the number of hydrazine molecules is the results of the compromise between the decomposition temperature and the violence of decomposition. It is desired a low decomposition temperature but also a control of the decomposition reaction is necessary. The presence of water is necessary because it is a moderator for thermal decomposition and it favours the yielding of oxide materials. The analyses show the presence of a homogenous compound with characteristic properties and well crystallised spinel structure, with formula CoFe2O4.
Presentation: Poster at E-MRS Fall Meeting 2007, Symposium A, by Dragos-Viorel Brezoi
See On-line Journal of E-MRS Fall Meeting 2007
Submitted: 2007-05-20 19:02 Revised: 2009-06-07 00:44