Microstructure of melt-spun Nd-Fe-B magnequench magnets

An electron microscopy characterization of the melt-spun MAGNEQUENCH magnets shows that the best magnetic properties are obtained in materials with a two-phase microstructure where 20–30 nm size Nd2Fe14B grains are completely surrounded by a 1–2 nm thick amorphous film of Nd rich and B deficient phase. It is shown that this phase acts as a pinning site for the magnetic domain walls.