The coercivities of nanophase melt-spun PrFeB alloys

The effects of the mean Pr2Fe14B crystallite size (d(g)) and alloy composit ion on the magnetic properties of a series of nanocrystalline melt-spun Prx Fe94-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) inc reases with decreasing d(g) up to a maximum, at which vitrification is init iated. Except for the single phase near-stoichiometric alloy, the intrinsic coercivity also rises with decreasing d(g). The composition dependencies o f J(r) and H-j(c) for d(g) generally in the range 20-30 nm are compared wit h those for corresponding NdFeB alloys. Significantly better combinations o f H-j(c) and maximum energy product (BH)(max) are obtained for the PrFeB th an for the NdFeB resulting from the higher anisotropy field of the Pr2Fe14B phase. (C) 1998 Elsevier Science S.A. All rights reserved.