Title :
Top Nd-Fe-B magnets with greater than 56 MGOe energy density and 9.8 kOe coercivity
Author :
Rodewald, W. ; Wall, B. ; Katter, M. ; Uestuener, K.
Author_Institution :
Vacuumschmelze GmbH & Co. KG, Hanau, Germany
fDate :
9/1/2002 12:00:00 AM
Abstract :
Sintered Nd-Fe-B magnets are prepared by powder metallurgy. Besides the composition of the alloy, the alignment of the powder particles is decisive for achieving high remanent polarizations. The alignment of the powder particles can be improved by applying field pulses in addition to an alignment in a constant magnetic field. Alternating field pulses parallel and antiparallel to the easy axis proved to be more efficient than unidirectional field pulses. By such a refined processing route sintered Nd-Fe-B magnets with a remanent polarization of 1.519 T, a coercivity HcJ of 7.8 kA/cm (9.8 kOe), and a maximum energy density of 451 kJ/m3 (56.7 MGOe) could be prepared.
Keywords :
boron alloys; coercive force; ferromagnetic materials; grain size; iron alloys; magnetic anisotropy; neodymium alloys; permanent magnets; powder metallurgy; remanence; sintering; 1.519 T; 56.7 MGOe energy density; 9.8 kOe coercivity; Nd-Fe-B; alternating field pulses; composition; constant magnetic field; easy axis; field pulses; high remanent polarizations; permanent magnets; powder metallurgy; powder particle alignment; refined processing; sintered Nd-Fe-B magnets; top Nd-Fe-B magnets; unidirectional field pulses; Anisotropic magnetoresistance; Coercive force; Disk drives; Iron alloys; Magnetic fields; Neodymium; Permanent magnets; Polarization; Powders; Temperature measurement;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2002.803075
