Iron nanoparticles prepared from natural ferrihydrite precursors: kinetics and properties
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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 Mössbauer 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.
KeywordsIron nanoparticles Ferrihydrite Reduction Hydrogen Magnetic moment Activation enthalpy
This work has been supported by the projects of the Ministry of Education of the Czech Republic (1M619895201) and Grant Agency of the Czech Republic (106/08/1440).
- Bowen LH, De Grave E, Vandenberhe RE (1993) Mössbauer effect studies of magnetic soils and sediments. In: Long GJ, Grandjean F (eds) Mössbauer spectroscopy applied to magnetism and materials science, vol 1. Plenum Press, New York, pp 115–159Google Scholar
- Cornell RM, Schwertmann U (1996) The iron oxides. Structure, properties, reactions occurrence and use. VCH, Weinheim, p 117Google Scholar
- Schneeweiss O, Grygar T, David B, Zboril R, Filip J, Mashlan M (2008) Mössbauer and magnetic studies of nanocrystalline iron, iron oxide and iron carbide powders prepared from synthetic ferrihydrite. In: Mashlan M, Zboril R (eds) Mossbauer spectroscopy in materials science 2008, AIP conference proceedings, vol 1070, pp 106–113Google Scholar
- Schneeweiss O, Hapla M, Zboril R, Maslan M (2010a) Properties of iron nanoparticles sealed in protective media. In: Müller H, Reissner M, Steiner W, Wiesinger G (eds) Proceedings of the ICAME 2009, IOP Publishing, J Phys Conference Series 217. doi: 10.1088/1742-6596/217/1/012104
- Schneeweiss O, David B, Žák T, Filip J, Tuček J, Zbořil R, Mašláň M (2010b) Magnetic interactions between nanoparticles formed during calcination of ferrihydrite. Acta Phys Polon A 118:749–750Google Scholar
- Trujic VK, Zivkovic ZD, Zivkovic DT (1996) Influence of hydrated lime on the reduction of green magnetite pellets with hydrogen. Mater Trans JIM 37:1580–1587Google Scholar
- Wagner D, Devisme O, Patisson F, Ablitzer D (2006) A laboratory study of reduction of iron oxides by hydrogen. In: Kongoli F, Reddy RG (eds) Proceedings of the Sohn international symposium, 27–31 August 2006, vol 2. TMS, San Diego, pp 111–120Google Scholar