High-coercivity SmCo5/α-Fe nanocomposite magnets

Bulk nanocomposite SmCo5/α-Fe magnets were produced by the spark plasma sintering method from SmCo5/α-Fe nanocomposite powders, which were prepared by ball milling of SmCo5 and Fe powders. Although the SmCo5/α-Fe nanocomposite powders did not show high coercivity, the bulk magnets produced from them by the spark plasma sintering method exhibited high coercivity. Synchrotron radiation X-ray diffraction studies revealed that the SmCo5 phase was transformed into the Sm2Co17 phase after sintering at 973 K. The bulk nanocomposite magnet produced at 873 K consisted of the Fe and SmCo5 phases, while that produced at 973 K consisted of the FeCo and Sm2Co17 phases. It was found that the bulk nanocomposite SmCo5/α-Fe magnet produced at 873 K exhibited a high remanence of 83.1 Am2/kg with a high coercivity of 0.98 MA/m.