STRUCTURE AND MAGNETIC-PROPERTIES OF MECHANICALLY MILLED ND2XFE100-3XBX (X=2-6)

The effects of composition and heat treatment on the structure and mag netic properties of mechanically milled Nd2xFe100-3xBx alloys (x = 2-6 ) have been studied. High remanences have been obtained in isotropic s amples consisting of a nanocrystalline mixture of Nd2Fe14B and alpha-F e. For optimally heat treated samples, an increase in the volume fract ion of alpha-Fe from 14% to 73%, increased the reduced remanence (M(r) /M(s)) from 0.56 to 0.64. The corresponding coercivities decreased fro m about 8 kOe to only 1.6 kOe. The magnetic behaviour of these Nd2Fe14 B-alpha-Fe alloys is associated with exchange coupling between the har d and soft magnetic phases.