Hard magnetic properties and microstructures of melt-spun SmCo5Fex(x= 0, 1 and 2) ribbons

Three Fe-rich SmCo 5 Fe x ( x = 0, 1 and 2) ribbons were prepared directly by melt spinning using a wheel speed of 25 m s -1 . The x = 2 ribbons possessed the best hard-magnetic properties, intrinsic coericivity 8.2 kOe, saturation magnetization 117.72 emu g -1 , and maximum energy product 16.06 MGOe. The microstructures were investigated by transmission electron microscopy. The x = 0 ribbons showed striated grains with varied compositions, such as SmCo 5 , SmCo 3 , Sm 54 Co 46 , etc. In contrast, the x = 1 and 2 ribbons showed cellular microstructures. However, the boundary phases were found to be different, Sm(Co,Fe) 3 for the x = 1 ribbons and both Sm(Co,Fe) 3 and Sm 2 (Co,Fe) 7 for the x = 2 ribbons. The correlation between magnetic properties and microstructures is discussed in detail. The coercivity mechanism is explained according to the temperature dependence of coercivity by the nucleation model. In turn, the dependence of the small microstructure parameters k and N eff on intergrain exchange coupling were analysed in nanoscale grains of SmCo 5 Fe 2 ribbons.