A new Sm–Co-type hard magnetic alloy with an amorphous based nanocrystalline microstructure

Sm–Co–Al amorphous alloys with high Sm content have very low coercivity at room temperature (RT). In this paper, Sm11.6Co60.7Fe15.7Zr7Cu1B4 alloys with low level of Sm and mixed addition of several elements were prepared via arc melting, copper mold casting and rapid quenching technique, respectively. The ribbons melt-spun at 40 m/s present a novel microstructure with Sm(Co,M)7 and other minor nanocrystalline phases embedded in the amorphous matrix, which makes the average coercivity reach up to 18.2 ± 1.6 kOe at RT. The temperature dependence of magnetization curves of the ribbons suggest a high content of amorphous phase which is stable and behaves ferromagnetism below 500 °C.