Coercivity enhancement in boron-enriched stoichiometric REFeB melt-spun alloys

Considerable enhancement of magnetic properties was attained ill initially stoichiometric nanophase RE12Fe82B6 melt-spun alloys (RE = Nd, Nd + Pr) by means of an excess B content (10 at%) and additions of Zr and Co (2% and 7% respectively). The intrinsic coercivity exhibited a marked improvement (with respect to the stoichionmetric 6 at%, B alloy), within the range 50-65%,, With a maximum of 1161 +/- 14 kA m(-1) for the B-rich and Zr-containing alloy, to-ether with all excellent combination of remanence and energy density values of 0.90 +/- 0.01 T and 137 +/- 4 kJ m(-3), respectively. Further Co addition led to a CLlrie telilperature increase. while preserving high coercivity (1176 +/- 31 kA m(-1)) arld Useful energy densities (119 +/- 4 U kJ m(-3)). Results were interpreted oil the basis of alloy microstructural features and on variations of the intrinsic magnetic properties, supported by micromagnetic calculations. (c) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.