Title :
Coercivity enhancement of boron nitride doped Nd15Fe77B8 permanent magnets
Author :
Chen, S.K. ; Chin, T.S. ; Heh, S.J. ; Lin, K.D.
Author_Institution :
Dept. of Mater. Sci & Eng., Nat. Tsing Hua Univ., Hsinchu, Taiwan
fDate :
9/1/1990 12:00:00 AM
Abstract :
It is demonstrated that a small addition of boron nitride is effective in increasing the iHc value of Nd-Fe-B magnets. With the optimal addition of 0.1 wt.% BN, a maximum 20% increase in iHc and a slight increase in B r are obtained; hence, (BH)m is slightly enhanced. Chemical compositions estimated by Auger spectroscopy and EPMA (electron probe microanalysis) indicate that the boron concentration is higher at grain boundaries. The higher concentration of boron may be due to the fact that BN particles react with Nd and dissolve in the Nd-rich phase during heating processes. Although the dissolved BN contributes to slight grain refining, the coercivity mechanism might be attributed to the change in composition, notably an increase of NdN and NdB6, and morphology of the intergranular phase
Keywords :
boron alloys; boron compounds; coercive force; ferromagnetic properties of substances; iron alloys; neodymium alloys; permanent magnets; Auger spectroscopy; BN; EPMA; Nd-rich phase; Nd15Fe77B8; coercivity mechanism; composition; electron probe microanalysis; grain boundaries; grain refining; heating processes; intergranular phase; morphology; permanent magnets; Boron; Chemicals; Coercive force; Electrons; Grain boundaries; Heating; Magnets; Neodymium; Probes; Spectroscopy;
Journal_Title :
Magnetics, IEEE Transactions on
