Lanthanide intermetallics, which display the large magnetic anisotropies needed for high-field permanent magnets, are usually synthesized by reaction-diffusion processes that require the removal of components previously introduced to accelerate these transformations. For example, the synthesis of the ternary material Nd2Fe14B with CaH2 necessitates the removal of the calcium ions. Kim et al. report the aqueous synthesis of this intermetallic by sodium borohydride reduction of the metallic chlorides to form an easily isolable amorphous nanoparticulate product, which they characterized by electron microscopy and a range of diffraction techniques. The authors argue that electrostatic coupling of the Nd(III) ion with an initially formed Fe-B alloy helps to overcome the high reduction potential of the lanthanide ion to the corresponding metal. Heating of the product converts these soft magnets into a ferromagnetic material with higher coercivity. -- PDS
J. Am. Chem. Soc. 129, 10.1021/ja0706347 (2007).
