Influence of Fe Content on Microstructure and Magnetic Properties of Melt-Spun SmCo-Based Alloy Ribbons

The microstructure and magnetic properties of melt-spun Sm(Co0.88-xFexCu0.10Zr0.02)7.5 (x = 0.1 and 0.2) alloy ribbons have been studied. The results showed that the as-spun ribbons were in a single phase, SmCo7, with the Cu7Tb structure. When aged in the temperature range from 720 to 900 °C, the SmCo7 phase transformed into Sm2Co17, SmCo5, and CoFe(Zr) phases with a minor Sm2Co3 phase. For the x = 0.1 alloy, a large coercivity, Hc = 8.7 kOe, was observed although the soft magnetic CoFe(Zr) phase was present in the alloy. The volume fraction of the CoFe(Zr) phase increased when the ageing temperature increased from 720 to 760 °C. At higher ageing temperature, the CoFe(Zr) phase was partially re-dissolved. With an increase in the Fe content in the alloy, the CoFe(Zr) phase increased significantly, causing the coercivity to decrease.