The hard magnetic properties of nanocrystalline Fe-Nd-B alloys containing α-Fe and intergranular amorphous phase were investigated. The remanence was found to have a maximum value of 1.17 T. The precipitated crystallites have the particle sizes of 20 to 60 nm and the thickness of the intergranular amorphous layer is 5 to 30 nm. Further increase in annealing temperature and annealing time causes the increase in particle size of their precipitates as well as the disappearance of the residual amorphous phase. The intergranular amorphous phase as well as the bcc-Fe phase is presumed to act as an effective magnetic exchange-coupled medium.
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