Development of microstructure during desorption-recombination (DR) stages in hydrogenation-disproportionation-desorption-recombination (HDDR) process of Nd-Fe-B-based alloys

摘要

Relationship between coercivity and microstructural changes during the desorption-recombination (DR) stage in a hydrogenation-disproportionation- desorption-recombination (HDDR) processed Nd-Fe-B-based alloys was studied by a vibrating sample magnetometer (VSM), hydrogen content measurement by a thermal desorption spectroscopy (TDS), a positron lifetime spectroscopy, an X-ray diffraction (XRD), and cross sectional observation by a scanning electron microscopy (SEM). These results suggest that, after the recombination reaction to Nd_(2)Fe_(14)B phases have been almost completed, Nd-rich phases have formed along boundaries of the newly- formed Nd_(2)Fe_(14)B fine grains. These Nd-rich phases should play the important role to the coercivity in the HDDR-processed Nd-Fe-B-based alloys.