Title :
The effect of V or W additives to microstructure and coercivity of Nd-Fe-B based magnets
Author :
Bernardi, Johannes ; Fidler, Josef ; Födermayr, Franz
Author_Institution :
Inst. of Appl. & Tech. Phys., Tech. Univ. Vienna, Austria
fDate :
9/1/1992 12:00:00 AM
Abstract :
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
Keywords :
Curie temperature; X-ray chemical analysis; alloying additions; boron alloys; coercive force; ferromagnetic properties of substances; iron alloys; neodymium alloys; permanent magnets; precipitation; transmission electron microscope examination of materials; Curie temperature; Nd-Fe-B magnets; Nd-rich intergranular phase; NdDyFeCoB:Al,V; NdDyFeCoB:Al,W; X-ray microanalysis; coercivity; corrosion resistance; hard magnetic phase; intergranular WFeB phase; microstructure; precipitates; Coercive force; Corrosion; Iron; Magnetic force microscopy; Magnetic properties; Magnets; Microstructure; Scanning electron microscopy; Temperature sensors; Transmission electron microscopy;
Journal_Title :
Magnetics, IEEE Transactions on
