Mechanochemical reduction of nickel ferrite

The changes in nickel ferrite (NiFe2O4) due to high-energy milling in a sta inless steel vial have been investigated by Mossbauer spectroscopy. X-ray d iffraction (XRD). and thermal analysis. The milling process reduces the ave rage crystallite size of NiFe2O4 to the nanometer range. The Mossbauer spec tra show the formation of metallic iron and of a phase containing Fe2+ ions . The fraction of the reduced products increases with increasing milling ti me. The range of thermal stability of the metastable milled reduction produ cts has been determined by studying their response to changes in temperatur e. (C) 2001 Elsevier Science B.V. All rights reserved.