Title :
Magnetic properties on sintered permanent magnets R-Fe-Cu-B (R=Pr, Nd)
Author :
Lin, C.H. ; Chen, C.J. ; Wu, C.D. ; Chang, W.C. ; Chen, S.K. ; Chin, T.S.
Author_Institution :
Mater. Res. Lab., Ind. Technol. Res. Inst., Hsinchu, Taiwan
fDate :
9/1/1990 12:00:00 AM
Abstract :
Radially anisotropic Pr15Fe77.5Cu1.5 B6 permanent magnets have been prepared from hydrogen decrepitated (HD) powders by conventional powder metallurgy processes. The best magnetic properties obtained along the radial directions are as follows: (BH)max=10.5 MG-Oe, Br=7.5 kG, and iHc=8.5 kOe. Since Pr2(Fe,Cu)14BHx exhibits planar anisotropy, the tetragonal c-axis of the HD powders should lie in the plane perpendicular to the field direction during alignment compaction. This style of radial alignment is not changed in the subsequent dehydrogenation and sintering processes. The easy direction of magnetization of the magnet can be changed by alloy design, switching from radial directions to the field direction with the addition of 33 wt.% or more of Nd-Fe-B. Further addition of Nd-Fe-B monotonically increases both Br and (BH)max. For the Nd-Fe-Cu-B system, a small concentration of 1.5 at.% Cu dramatically deteriorates the magnetic properties of the sintered magnet due to the extensive precipitation of free iron
Keywords :
boron alloys; copper alloys; ferromagnetic properties of substances; iron alloys; magnetisation; neodymium alloys; permanent magnets; praseodymium alloys; HD powders; Nd-Fe-Cu-B; Pr15Fe77.5Cu1.5B6; alignment compaction; alloy design; dehydrogenation; magnetic properties; magnetization; planar anisotropy; powder metallurgy processes; precipitation; radial alignment; radial directions; sintered permanent magnets; sintering; Anisotropic magnetoresistance; Compaction; High definition video; Hydrogen; Iron; Magnetic anisotropy; Magnetic properties; Permanent magnets; Perpendicular magnetic anisotropy; Powders;
Journal_Title :
Magnetics, IEEE Transactions on
