Co-substituted Nd-Fe-B magnets show an increased Curie temperature. The coercivity of these magnets is reduced due to the formation of Co-rich phases. In addition to the hard magnetic phase the Nd-rich intergranular phase exists, which results in bad corrosion resistance. In (Nd,Dy)-(Fe,Co)-B:Al type magnets doped with V, (V1-xFex)3B2 intergranular phases and precipitates with Si2U3 structure and a Nd-rich Co-containing phase partly replacing the Nd-rich phase were found. X-ray microanalysis shows that in (Nd,Dy)-(Fe,Co)-B:(Al,V) magnets Dy is mainly dissolved in the hard magnetic phase. Comparison with W-doped Nd-Fe-B magnets shows that W also forms an intergranular WFeB phase with Co2Si-structure and precipitates within the hard magnetic phase with presumably the same composition
Published in:
Magnetics, IEEE Transactions on
(Volume:28
,
Issue:
5
)
Date of Publication: Sep 1992