Letter 1656

Neodymium-Ferrite-Boron electroplating

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In China, the annually turnover of Neodymium magnet is more than 1000TONs. But now, most of the factories could not coating well enough.

Our factory is using Nickel coating, as the Neodymium-Ferrite-Boron is sintering like powder metallurgy, the molecule is different from the usually metal. Our products rejected several times by oversea customers due to the coating problem.

Some experts told me to try coating double deck, copper first, then Nickel. But I do not know how the technics.

Would any body give me some suggestion and technics support?

Sun Yi-Chun
- Ningbo, China

I don't know about the need for a copper undercoat, but I would think that even this would not properly seal the porosity in sintered metal objects. Have you considered vacuum impregnation?

Ted Mooney, P.E.  finishing.com Brick, NJ

We have investigated numerous coatings suitable for this aplication and have concluded that electrophoretic painting is the prefered option. We use a special pre-treatment route to acheive this.

Robert W Bayston
- Cheltenham, Gloucesteshire, UK

Our shop has successfully Loctite impregnated powdered metal parts for many years. The reasons for impregnation would include: Improved coatability, Sealability, Increased machinability, Added strength, Solvent resistantance, and Adhesion properties. We have a rather large customer that we impregnate Iron-Boron-Neodymium magnets for: solvent resistance is their main concern. The process calls for: proper materials, cleanliness, proper vacuum/pressure/durations, proper cleaning process, and possibly a post cure.

Gene Muenchausen
- Madison Hts., Michigan

I agree with Gene. Impregnation will greatly improve the coatability of your parts. Good luck!

Joe Babcock
- Ann Arbor, MI, USA

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