Boron Enriched ${\rm RE}_{2}{\rm Fe}_{14}{\rm B}$ -Base Melt Spun Alloys With Intrinsic Coercivities Over 1000 kA/m

Considerable enhancement of magnetic properties was attained in nanophase RE₁₂Fe₈₂B₆ -base melt spun alloys (RE=Nd,Nd+Pr) by means of B excess content (10 at%) and Zr-Co addition (2% and 7%, respectively). The intrinsic coercivity exhibited a marked improvement (respect to the stoichiometric 6 at% B alloy) within the range 50%-65%, with a maximum of 1161 plusmn 14 kA/m for the B-rich and Zr-containing alloy, together with an excellent combination of remanence and energy density values of 0.90 plusmn 0.01 T and 137plusmn4 kJ/m³, respectively. Further Co addition led to a Curie temperature enlargement (350^degC) preserving high coercivity (1176 plusmn 31 kA/m) and useful energy densities (119plusmn4 kJ/m³). Results were interpreted on the basis of microstructure and intrinsic magnetic property variations, together with micromagnetic calculations.