Injection-molded Sm–Fe–N anisotropic magnets using unsaturated polyester resin

Abstract New injection-molding technology has been developed using an unsaturated polyester (UP) resin in order to produce bonded Sm–Fe–N anisotropic magnets. Sheet magnets of 50 mm × 20 mm × 0.36 mm are successfully made within a cycle time of 90 s. Magnetic properties obtained are almost the same as those obtained in column magnets of ϕ10 mm × 7 mm. Typical data of magnetic properties are as follows: Br = 0.72 T, HCJ = 796 kA/m and (BH)max = 94.7 kJ/m3. The density is 4.79 Mg/m3. The degree of orientation of (0 0 6) is 5.31 calculated using the Wilson formula from X-ray diffraction result. Ring magnets of 7.4 mm × 3.2 mm × 0.3 mm are easily made from sheet magnets.