The coercivities of nanophase melt-spun PrFeB alloys

The effects of the mean Pr2Fe14B crystallite size (d(g)) and alloy composition on the magnetic properties of a series of nanocrystalline melt-spun PrxFe94-xB6 alloys (with 6 less than or equal to x less than or equal to 20 at%) have been investigated. In all cases, the remanent polarisation J(r) increases with decreasing d(g) up to a maximum, at which vitrification is initiated. Except for the single phase near-stoichiometric alloy, the intrinsic coercivity also rises with decreasing d(g). The composition dependencies of J(r) and H-j(c) for d(g) generally in the range 20-30 nm are compared with those for corresponding NdFeB alloys. Significantly better combinations of H-j(c) and maximum energy product (BH)(max) are obtained for the PrFeB than for the NdFeB resulting from the higher anisotropy field of the Pr2Fe14B phase. (C) 1998 Elsevier Science S.A. All rights reserved.