NUCLEAR-MAGNETIC-RESONANCE AND MOSSBAUER STUDIES OF RAPIDLY QUENCHED AND HEAT-TREATED ND4FE77.5B18.5 ALLOYS

Using the Mossbauer effect and NMR, and phase compositions of rapidly quenched Nd4Fe77.5B18.5 alloy under different heat treatment conditions were studied. It was shown that the sample which was annealed at 670 degrees C for a short time and has the optimal magnetic properties has a main BCT Fe3B phase containing Nd atoms and a small amount of alpha -Fe (6%). It is concluded that the hard magnetic properties of crystallized melt-quenched Nd-Fe-B with a low Nd concentration do not originate from the presence of the hard magnetic Nd2Fe14B phase but from the BCT Fe3B phase containing Nd atoms.