Magnetic properties of SmCo5−xFex (x = 0–4) melt-spun ribbon

• SmCo5−xFex alloys were produced by melt-spinning and subsequent annealing.
• The Sm(Co,Fe)5 phase can be obtained up to x = 2 in SmCo5−xFex alloys.
• The SmCo2Fe3 alloy consisted of very fine grains of the Sm(Co,Fe) 7 and Fe phases.
• The SmCo2Fe3 nanocomposite magnet exhibited a high remanence of 100 emu/g.

SmCo5−xFex (x = 0–4) alloys were produced by melt-spinning and subsequent annealing. It was found that the small substitution of Fe for Co in the SmCo5 alloy results in the formation of the Sm(Co,Fe)5 phase, but that the large substitution of Fe for Co results in the formation of other phases such as the Sm(Co,Fe)7 and Sm2(Co,Fe)7 phases. The remanence of the annealed SmCo5−xFex melt-spun ribbons increased from x = 0 to x = 3 then decreased with increasing Fe content, while their coercivity decreased as the Fe content increased. Transmission electron microscope (TEM) studies revealed that the annealed SmCo4Fe melt-spun ribbon consisted of relatively coarse Sm(Co,Fe)5 grains, whereas the annealed SmCo2Fe3 melt-spun ribbon consisted of a mixture of extremely fine grains of the Sm(Co,Fe)7 and Fe phases. The annealed SmCo4Fe alloy with the Sm(Co,Fe)5 phase showed a high coercivity of 10.2 kOe with a remanence of 60 emu/g, while the annealed SmCo2Fe3 alloy formed a nanocomposite magnet with a high remanence of 100 emu/g and a coercivity of 2.9 kOe.