Production of bulk nanocomposite magnets of an Nd4Fe77.5B18.5 alloy by compression shearing method

Amorphous melt-spun ribbons of an Nd₄Fe_77.5B_18.5 alloy were successfully transformed into bulk material by a compression shearing method. The resultant bulk material showed a low coercivity, as would be expected for an amorphous Nd-Fe-B material. Heat treatment of the amorphous bulk material above the crystallization temperature resulted in the formation of a metastable Fe₃B phase together with an Nd₂Fe₁₄B phase. The resultant nanocomposite magnets exhibited a coercivity as high as 2.4 kOe, as was the case for the annealed melt-spun ribbon. It was found that such a bulk nanocomposite magnet with a high coercivity could be directly produced from annealed melt-spun ribbon by the compression shearing method.