Fully dense isotropic and anisotropic (Nd,Pr,Dy) 2 Fe 14 B/ -Fe nanocomposite magnets have been successfully prepared by a hot press and hot deformation technique using melt-spun precursors. For the fully dense, hot-deformed, anisotropic nanocomposite (Nd,Pr,Dy) 2 Fe 14 B/ -Fe-based magnets containing 4 vol% and 11 vol% -Fe, the maximum energy products have reached 31 and 24 MGOe, respectively. At the time of proofreading for this paper, 42 MGOe has been reached for the nanocomposite magnets with~4 vol% -Fe.

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Chemical coating, hot compaction, and hot deformation techniques have been applied to prepare bulk isotropic and anisotropic Nd2Fe14B∕α-Fe nanocomposite magnets. The effect of α-Fe content on the structure and magnetic properties of the magnets were studied. For the isotropic magnets, the remanence (Br) increases as the α-Fe content increases, while the coercive force (Hci) drops simultaneously. For the anisotropic magnets, the Br rises first, peaking at 2vol% of α-Fe content, then falls as the α-Fe content increases, and Hci drops significantly for all the α-Fe containing anisotropic magnets. Crystal structure analysis shows that only the magnets with no more than 2vol% α-Fe exhibit strong c-axis crystal texture of Nd2Fe14B phase after deformation. Microstructure observation also shows that there are many Nd2Fe14B equiaxial grains even after hot deformation in the magnets with α-Fe more than 2vol%.

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