Hard magnetic properties of the rapidly quenched Sm(Co-Fe-B)5alloy ribbons

The structure and hard magnetic properties of the rapidly quenched SmCo5-xBx( ) and Sm(Co1-xFex)4B ( ) alloy ribbons fabricated under various quenching rates were systematically examined. Metastable states, such as CaCu5type disordered structure and amorphous state were found in a wide composition range, for SmCo5-xBxand for Sm(Co1-xFex)4B in the ribbons fabricated under high quenching rate. The maximum Value ofiHc(>18kOe) was obtained for ribbons which consist of the CaCu5disordered structure as a single phase. Furthermore, in the case of CaCu5disordered structure, the value of Tcremarkably increased with increasing Fe and decreasing B content. (SmCo4B (Tc=197°C) → SmCo4.4B0.6(Tc=557°C)/Sm(Co0.5Fe0.5)4B (Tc=472°C)). The value of M(Hex=18kOe) also increased with increasing Fe and decreasing B content. It was concluded that the formation of CaCu5type disordered Sm(Co-Fe-B)5compound with high Fe and low B content was considered to be effective to improve the hard magnetic properties of Sm-Co based alloys.