Characterization of the disproportionated NdFeCoZrB alloy by means of electron microscopy

The microstructure of the disproportionated NdFeCoZrB alloy during the solid-HDDR (hydrogenation-disproportionation-desorption-recombination) process was investigated by means of scanning electron microscope (SEM) and transmission electron microscope (TEM). Except for a similar colony-type structure to ternary alloy, fine particles including spherical (Fe, Co)(2)B phase and undecomposed rim-like Nd-2(Fe, Co)(14)B compound were found dispersed within the alpha-(Fe, Co) matrix of the microstructure of the disproportionated NdFeCoZrB alloy. An unknown Fe-rich phase with a comparable size to that of the matrix grain was also detected by electron diffraction. These results strongly suggest that the undecomposed rim-like Nd-2(Fe, Co)(14)B particles are probably the memory sites for the origin of anisotropy of the received NdFeCoZrB materials.