Fe-Si and its nanocrystallization as soft magnetic phase in SmCo-based nanocomposites

Nanocomposite magnets have attracted much attention because of their ultra-high theoretical magnetic energy product and saving rare earth resources. In this study, the Fe93.5Si6.5 with higher hardness than the most common soft magnetic phase (α-Fe) was used to synthesize SmCo5/Fe-Si nanocomposite magnets, and its nanosized process was studied. The results showed that Fe-Si can be well dispersed into SmCo5 matrix through 12 hours of ball milling, and appeared in fine and evenly distributed grains in the SmCo5/Fe-Si nanocomposites, indicating it is suitable for soft magnetic phase. The nanosized process of Fe-Si phase can be summarized as from the irregular shape of agglomeration, to long chain, and finally too uniformly dispersed Fe-Si particles with increased milling time. As a result, the SmCo5/Fe-Si nanocomposite magnet with the optimal maximum magnetic energy product was 14.3 MGOe, accompanied by remanence of 9.5 kG and coercivity of 8.2 kOe. Our results show that by using Fe-Si with high hardness as the soft magnetic phase, the prepared nanocomposite magnet not only has good properties, but also can be expected that the two phases with closer mechanical properties can be deformed harmoniously.