A Novel Route for the Preparation of Nanocomposite Magnets

Evolution of interface structure ofα−Fe/Nd2FeZhang1, Guan2, Zhang3 et al. 2002Phys. Rev. B341230View full textAdd to dashboardCite

“…2,3 The energy products obtained at present in nanocomposite magnets, however, are only in the range of 10-25 MG Oe. 4,5 Since the physical and mechanical properties of nanostructured materials depend closely on their interface structure, 6 a profound knowledge regarding the interface structure of the nanocomposite magnets is required for a detailed understanding of the discrepancy between the predicted and actual energy products. Positron lifetime spectroscopy has been proven to be a sensitive and specific tool for the study of interface structure, e.g., the interfacial free volume in nanostructured solids.…”

Enhancement of the maximum energy product of α-Fe∕Nd2Fe14B nanocomposite magnets by interfacial modification

“…To improve the interfacial structure, in the present study, we produce an interfacial amorphous phase with a volume fraction of 14%-16% in ␣-Fe/ Nd 2 Fe 14 B nanocomposites by a proper addition of Nb in the melt-spun NdPrFeCoB. 4,[7][8][9] Recently, positron annihilation studies show that 10,11 the dominating interfacial structure in nanocomposite magnets has a loosely packed atomic structure with vacancy-sized free volumes, which will weaken the magnetic exchange coupling between the soft-and hard-magnetic grains 12 and reduce the anisotropy constant near grain surfaces, 13 and thus lead to a low energy product for the magnets. 2 Nanocomposite exchange coupled magnets consisting of a fine mixture of hard-and soft-magnetic phases 1 have attracted much attention for the development of permanent magnets since a high maximum energy product above 50 MG Oe would be expected in the magnets.…”