Rare earth magnets resisting eddy currents

Journal Article · Wed Sep 01 04:00:00 EDT 1999 · IEEE Transactions on Magnetics (Institute of Electrical and Electronics Engineers)

DOI:https://doi.org/10.1109/20.800519· OSTI ID:20000769

Pan, W; Li, W; Cui, L Y; Li, X M; Guo, Z H

Magnets with high electrical resistance were prepared by electrically isolating Sm{sub 2}Co{sub 17} and Nd{sub 2}Fe{sub 14}B powder particles. It is done by a polymer mixture consisting of epoxy polyester-insulant (EPI), polyvinylbutyral (PVB), epoxy resin (ER) and silane coupling (SC). The properties of interest for anisotropic Sm{sub 2}Co{sub 17} and isotropic Nd{sub 2}Fe{sub 14}B magnets respectively are {rho} = 1 x 10{sup 5} {Omega} {minus}cm{sup 2}/m, Br = 6.8 kGs, {sub 1}H{sub c} = 10.0 kOe, (BH){sub max} = 9.2 MGOe in 5% EPI, 4%PVB, 2%ER, 1%SC and {rho} = 9.4 x 10{sup 4} {Omega} {minus}cm{sup 2}/m, Br = 4.5kG, {sub i}H{sub c} = 9.5 kOe, (BH){sub max} = 4.3 MGOe in 4%EPI, 3%PVB, 2% ER, 1%SC. The insulated magnets exhibit far better magnetic stability than those of sintered and bonded magnets after magnetizing in radio frequency. The insulated Sm{sub 2}Co{sub 17} magnet has the best performance in resisting eddy current. In 500 kHz frequency, 830 Oe magnetizing-field and in one minute, the irreversible loss of recoil remanence is 1.47% and 22.2% respectively for insulated Sm{sub 2}Co{sub 17} and Nd{sub 2}Fe{sub 14}B magnets.

• Research Organization: Central Iron and Steel Research Inst., Beijing (CN)
• OSTI ID: 20000769
• Journal Information: IEEE Transactions on Magnetics (Institute of Electrical and Electronics Engineers), Journal Name: IEEE Transactions on Magnetics (Institute of Electrical and Electronics Engineers) Journal Issue: 5Pt2 Vol. 35; ISSN IEMGAQ; ISSN 0018-9464
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BORON ALLOYS
COBALT BASE ALLOYS
EDDY CURRENTS
ELECTRIC CONDUCTIVITY
IRON BASE ALLOYS
MAGNETIC PROPERTIES
NEODYMIUM ALLOYS
PERMANENT MAGNETS
SAMARIUM ALLOYS