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Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/4981

Title: Improvement of protective coating on Nd–Fe–B magnet by pulse nickel plating
Authors: Cheng, Chung-wai
Cheng, Fai Tsun
Man, H. C.
Subjects: Neodymium alloys
Iron alloys
Boron alloys
Ferromagnetic materials
Permanent magnets
Nickel
Electroplating
Corrosion protective coatings
Issue Date: 1-Jun-1998
Publisher: American Institute of Physics
Citation: Journal of applied physics, 1 June 1998, v. 83, no. 11, p. 6417-6419.
Abstract: Sintered Nd–Fe–B magnets were coated by pulse nickel plating at different plating conditions. Optimal pulse plating condition was established (average current density=1 A/dm², peak current density=6 A/dm² with T[sub on]:T[sub off]=1:2). In order to make a comparison, magnets with similar nickel coating thickness plated by dc were also prepared. The corrosion resistance of the coated magnets was evaluated by (i) Normal Salt Spray Test (5% NaCl, 35 °C) and (ii) potentiodynamic polarization measurement (3.5% NaCl solution). It was found that the corrosion resistance of the pulse nickel plated magnet was significantly improved as compared with that of the conventional dc plated ones, with negligible deterioration in magnetism. The microstructure of the coating was examined by optical microscopy and scanning electron microscopy. It was found that the porosity was much lower, and the grains much finer in the pulse-plated layer as compared with the dc plated ones.
Description: DOI: 10.1063/1.367921
Rights: © 1998 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in C. W. Cheng et al., J. Appl. Phys. 83, 6417 (1998) and may be found at http://link.aip.org/link/?jap/83/6417.
Type: Journal/Magazine Article
URI: http://hdl.handle.net/10397/4981
ISSN: 0021-8979 (print)
1089-7550 (online)
Appears in Collections:ISE Journal/Magazine Articles
AP Journal/Magazine Articles

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