Abstract
The Fe65B22Nd9Mo4 nanocomposite permanent magnets in the form of a rectangular cross sectioned rod have been prepared by annealing the amorphous precursors. The thermal behavior, structure and magnetic properties of the magnets have been investigated by differential scanning calorimetry, X-ray diffractometry, electron microscopy and magnetometry techniques. The as-cast Fe65B22Nd9Mo4 alloy showed soft magnetic properties, which changed into magnetically hard after annealing. Results provoke that the magnetic properties of the alloy are sensitive to thermal processing conditions. The optimum hard magnetic properties with a remanence (B-r) of 0.56 T, coercivity (H-i(c)) of 920.7 kA/m and maximum energy product (BH)(max) of 50.15 kJ/m(3) were achieved after annealing the alloy at 983 K for 10 min. The good magnetic properties of Fe65B22Nd9Mo4 magnets are ascribed to the exchange coupling between the nano-scaled soft alpha-Fe, Fe3B and hard Nd2Fe14B magnetic grains. (C) 2011 Elsevier B.V. All rights reserved.