Magnetic Properties and Crystal Orientation of Extruded Nd-Fe-B Magnets

A hot extrusion method was utilized to develop Nd-Fe-B permanent magnets suitable for radial or circumferential applications, such as in stepping motors. Billets produced by hot-pressing rapidly quenched powder were subjected to extrusion. A plane-anisotro-pic magnet was obtained by forward extrusion, and a radially anisotropic magnet by backward extrusion. The respective magnetic properties in the radial direction of these magnets were as follows: Br=0.895 T, iHc=860 kA/m and (BH)max=134 kJ/m³ for the former, and Br=1.065 T, iHc=520 kA/m and (BH)max=183 kJ/m³ for the latter.