High-coercivity Sm2(Fe,Al,Mo)17C1.5 ribbons with addition of Mo

The effects of Mo additions on the structure and magnetic properties of Sm2Fe(15.5-x)MoxAl1.5C1.5 alloys have been investigated by means of x-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, and magnetic measurements. The XRD analyses show that as-cast alloys consist mainly of a 2/17-type carbide and a considerable amount of alpha-Fe. Rapidly quenched, the Mo-containing alloys form a nanocrystalline structure with an average grain size of 35-50 nm, while the amount of the alpha-Fe phase is greatly decreased. The magnetic hardening of the Mo-containing alloys can be achieved by direct quenching. A coercivity exceeding 1.35 T is obtained for the Sm2Fe14.9Mo0.6Al1.5C1.5 ribbon spun at 40 m/s. These results reveal that the addition of Mo is effective in improving the coercivity. (C) 1998 American Institute of Physics.