Synthesis and magnetic properties of Ni3Fe intermetallic compound obtained by mechanical alloying

Nanocrystalline Ni3Fe intermetallic compound has been obtained by milling of iron and nickel powders under argon atmosphere. Several milling times have been used ranging from 1 h up to 52 h. The formation of the Ni3Fe intermetallic compound by mechanical alloying was evidenced by X-ray diffraction and Fe-57 Mossbauer spectroscopy. A heat treatment of 1 h at 330degreesC relaxes the first and second order internal stresses and favours the solid-state reaction. The reaction becomes significant after 4 h of milling and subsequent heat treatment. A typical particle size of 12.5 +/- 2.0 nm has been obtained after 52 h. Scanning electron microscopy and X-ray microanalysis studies show the evolution of the chemical homogeneity of the particles and reveal the morphology upon Ni3Fe phase formation. Magnetic measurements have been performed in a magnetic field up to 8 Tesla between 4 and 300 K. The influence of the synthesis conditions on the magnetic properties of Ni3Fe is discussed. (C) 2002 Elsevier Science B.V. All rights reserved.