Iron nanoparticles prepared from natural ferrihydrite precursors: kinetics and properties

0438028 - ÚFM 2015 RIV NL eng J - Journal Article
Schneeweiss, Oldřich - Filip, J. - David, Bohumil - Zbořil, R. - Mašláň, M.
Iron nanoparticles prepared from natural ferrihydrite precursors: kinetics and properties.
Journal of Nanoparticle Research. Roč. 13, č. 11 (2011), s. 5677-5684. ISSN 1388-0764. E-ISSN 1572-896X.
[International Conference on Nanostructured Materials (NANO 2010) /10./. Rome, 13.09.2010-17.09.2010]
Institutional research plan: CEZ:AV0Z20410507
Keywords : Iron nanoparticles * Ferrihydrite * Reduction * Hydrogen * Magnetic moment * Activation enthalpy
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 3.287, year: 2011

Natural ferrihydrite was used as the precursors for the preparation of the nanocrystalline alpha-Fe powder using heat treatment in hydrogen atmosphere. Transformation temperatures were estimated from the temperature dependences of magnetic moment. Structure and phase composition of the precursors and the final powders were characterized by X-ray diffraction and Mossbauer spectroscopy. Magnetic properties were characterized according to hysteresis loop parameters. The kinetics of the transformation was described using Avrami relation applied on the data of the isothermal time dependence of magnetic moment measurements and subsequently the activation enthalpy of transformation was estimated using Arrhenius plots of their parameters. Comparison of the changes of activation enthalpies derived from a different temperature ranges indicates effects of different processes on formation of alpha-Fe nanoparticles
Permanent Link: http://hdl.handle.net/11104/0241548