Novel Nd2Fe14B nanoflakes and nanoparticles for the development of high energy nanocomposite magnets

High energy ball milling has been shown to be a promising method for large-scale fabrication of rare earth-transition metal nanoparticles. In this work, magnetically hard Nd-Fe-B nanopowders with a coercivity in the range of 1.2-4 kOe have been produced by surfactant-assisted ball milling of nanocrystalline precursor alloys. The nanopowders consisted of Nd2Fe14B flakes with a thickness below 100 nm and an aspect ratio as high as 102-103 and anisotropic square nanoparticles with a size of 11 nm. Both the nanoparticles and nanoflakes showed a strong [001] out-of-plane texture. The nanoparticles showed a spin reorientation temperature which is lower (117 K) than the bulk value (135 K). The successful fabrication of Nd-Fe-B nano-thin flakes and anisotropic nanoparticles provides hope for the development of nanocomposite permanent magnets with an enhanced energy product.