Magnetic Properties of Anisotropic Pr-Fe-B Melt-Spun Ribbons

The magnetic properties and microstructure of Pr-Fe-B(Ga) melt-spun ribbons prepared by the single- or twin-roller method were studied. A texture with the c-axis normal to the surface was observed in slowly quenched ribbons, and showed a strong dependence on composition. Addition of Ga is effective for increasing the coercivity and the c-axis alignment of ribbons. Magnetic measurements of powders obtained by crushing ribbon samples prepared by the twin-roller method revealed that the powders solidified in a paraffin bath with a magnetic field of 12 kOe applied had a high coercivity of iH
c
=13.8 kOe and a higher remanence than did powders solidified without a field applied. Observations of the microstructure of cast alloys suggest that the strong c-axis alignment arises from the rapid quenching.