Atom Probe Characterization of an a-FelNdzFeldB Nanocomposite Magnet With a Remaining Amorphous Phase

The microstructural features of NdsFe76.sCosB6Cuo.sNbl nanocomposite magnet have been studied by a three-dimensional atom probe (JDAP) and transmission electron microscopy (TEM). The as-melt- spun microstructure is composed of a-Fe, NdzFe14B and a large fraction of intergranular amorphous phase. The annealed microstructure with optimum magnetic properties contains the same constituent phases as those in the as-quenched state, but the volume fraction of the NdzFelrB grains is increased by partial crystallization of the remaing amorphous phase. Nb and B are found to be enriched in the remaining amorphous phase. Unlike Fe3B/Nd2Fe14B nanocomposite, Cu additions are not effective in refining the grain size in this system. Index Termea-FelNd2Fe14B, amorphous, nanocompo- site magnet, exchange spring magnet