Title :
The effects of boron content on the microstructure and exchange coupling effect of Nd9.5Fe85.5-xB5+x melt spun ribbons
Author :
Chang, W.C. ; Hsing, D.M. ; Ma, B.M. ; Bounds, C.O.
Author_Institution :
Dept. of Phys., Nat. Chung Cheng Univ., Ming-Hsiung, Taiwan
fDate :
9/1/1996 12:00:00 AM
Abstract :
The magnetic properties, phases transformations and microstructural evolution of Nd9.5Fe85.5-xB5+x(x=0, 1, 3 and 4) alloy ribbons have been investigated. Excellent magnetic properties with a Br=11.7 kG, iHc=6.6 kOe, (BH)max=18.7 MGOe and Br=11.4 kG, iHc=6.3 kOe, (BH)max=19 MGOe, can be achieved in the alloys with x=0 and 1, respectively, simply from direct quenching. For alloy ribbons with higher boron content (x=3 and 4), the magnetic properties degrade and are lower than that of the former even after subsequent annealing. From X-ray diffraction, TEM and magnetic analysis, the degradation of magnetic properties was found to result from the formation of Fe3 B phase inside Nd2Fe14B and α-Fe phases and to grain coarsening leading to the reduction of the exchange coupling effect between Nd2Fe14B and α-Fe or Fe3B phases
Keywords :
X-ray diffraction; annealing; boron alloys; crystal microstructure; exchange interactions (electron); ferromagnetic materials; grain size; iron alloys; magnetic particles; neodymium alloys; permanent magnets; quenching (thermal); stoichiometry; transmission electron microscopy; B content; Nd9.5Fe85.5-xB5+x; Nd9.5Fe85.5B5; TEM; X-ray diffraction; annealing; exchange coupling; grain coarsening; magnetic properties; melt spun ribbons; microstructure; phase transformations; quenching; Annealing; Boron alloys; Couplings; Degradation; Iron alloys; Magnetic analysis; Magnetic properties; Microstructure; Neodymium; X-ray diffraction;
Journal_Title :
Magnetics, IEEE Transactions on
