Hard magnetic properties and coercivity mechanism of melt-spun Misch Metal-Fe-B alloy

•Melt-spun MM13Fe81B6 alloy shows that the distributions of the La, Ce, Pr, Nd, Fe and B elements is uniformly distributed, and the grain size is in the range of 30–40nm, it can be seen that Pr-rich and La-rich phases concentrated on grain boundaries, which resulted in the coercivity augment with the increase of MMFe2 content, and the grain size is around 40–50nm in MM16Fe78B6.•There is a significant formation of MMFe2 with abundant Pr and La, and a small amount of Ce and Nd enriched at the interfacial region in MM16Fe78B6, thus an inhomogeneous region was formed. It is considered that the inhomogeneous region is effective in increasing the coercivity.•The optimum-quenched MM13Fe81B6 alloy have been shown to exhibit a coercive force of 6.9kOe and an energy product of 8.5MGOe, which is superior to anisotropic ferrite magnets of 4.5MGOe.