Sensitivity of microstructure and magnetic properties to B content in SmCo_2.94FeCu_0.06B_x ribbons

This paper investigates the effect of B content on the phase transition, microstructure evolution, and magnetic properties of SmCo_2.94FeCu_0.06B_x (x = 0.8, 1.0, 1.2) ribbons. The results show that B addition changes the amorphous forming ability of the as-spun ribbons and the phase composition of the annealed ribbons. The microstructural analysis demonstrates that the x = 0.8 and x = 1.2 annealed ribbons are mainly composed of equiaxed grains, while the x = 1.0 annealed ribbons are composed of platelet-shaped grains. The x = 0.8 annealed ribbons obtain the highest saturation magnetization of 48.2 emu/g. The x = 1.0 annealed ribbons exhibit the highest coercivity of 50.1 kOe and remanenceof 24.5 emu/g, which is attributed to the platelet-shaped Sm-Co-B grains with a high magnetocrystalline anisotropy field, the strong pinning effect, and the strong exchange coupling between the hard magnetic phase. The annealed ribbons with low or high B content exhibit poor hard magnetic properties. Simultaneously, the mechanisms of B addition on magnetic properties are discussed.