Influence of modulated structure on magnetic properties of rapidly solidified Fe-Cr-Co permanent magnet ribbons

The Fe-22Cr-15Co-3Mo alloy melt was rapidly solidified to ribbons by a double roller technique. The texture of the ribbons was {100}<0vw>. After solution treatment, the ribbon was cut into small chips and thermomagnetically aged and then control-cooled. The maximum value of the coercive force was 500 Oe at 660°C for 30 min. The maximum value of (BH)max was 3.3 MGOe at 650°C for 60 min. The modulated structure was observed after the final aging by TEM. The modulated structures of adjacent grain boundaries showed misorientation with each other, whose cause was attributed to the addition of Mo. Experimental data indicated the validity of the theoretical analysis concerning the coercive force, uniaxial anisotropy constant and modulated structures.