Neodymium coatings




Surface treatment of neodymium magnets is an important process to be able to protect the magnet again corrosion. The substrate NdFeB (Neodymium, Iron, Boron) oxidizes rapidly without protective coatings. Below you will find a table with the most common surface treatments. Please contact us if you have any questions!

Material Salt spray test Thickness Appearance Properties
Nickel
Ni-Cu-Ni
>48hr 10-30µm Silver shiny
  • A standard surface treatment for neodymium magnets.
  • Suitable for indoor use.
  • Great performance/price ratio.
  • The surface treatment is with a copper (Cu) layer for better adhesion.
Zink
Zn
>24hr 6-15µm Silver/blue shiny
  • A standard surface treatment, with a more matte finish than Nickel.
  • Preferred if you need to avoid nickel (eg allergy) and need to have a slighty matte surface for better adhesion for eg marking and tape.
  • Suitable for indoor use.
  • Great performance/price ratio.
Epoxy
Ni-Cu-Epoxy
>96hr 10-30µm Black shiny
  • Perform better in humid environments.
  • More expensive production cost than NiCuNi and Zn, especially in smaller orders.
  • We use (on request) an extra layer (eg Ni-Cu-Ni-Epoxy) below the Epoxy to give the magnet further protection.
Gold
Ni-Cu-Au
>12hr 10-15µm Gold shiny
  • The gold plating is mostly for the look and does not directly have any practical function.
  • The price of this treatment is higher in comparison to NiCuNi and Zn.
Rilsan <1mm corrosion after 2000hr   Black shiny
  • The best surface treatment to protect against moisture. The default is black surface.
  • Rilsan/Thermoplastic means more production steps, longer production time and a more expensive final product.
  • The slighty thicker scratch/plastic surface gives the magnet a slighty worse dimension tolerance.
  • The safest treatment to use in for example, food production and where eg medical requirements are set, such as in dialysis machines.
Parylene >96hr 3-10µm Transparent
  • FDA-approved coating for use when the magnet should sit in the body.
  • Good protection against moisture, water and salt water. The coating will slowly but surely corrode in salt water, so an undercoating may be needed.
  • Relatively easy to get scratches/damage due to the thin coating, after that the magnet can corrode easily. Can be double treated with Parylene, but this increases the dimensions of the magnet. Check tolerances first.
Gummerad   0.5-1mm Black
  • If new/own dimension is wanted, this treatment is only produced in large quantitys since it needs a tool for a new dimension.
  • Improved shear force. Shock, scratch and water resistant! This makes it ideal for outdoor use and tough conditions.
  • Small sized magnets cannot be rubberized.
  • Since the thickness of the coating it has lower strength compared to a neodymium magnet of silimar dimension with other coating.
See all of our rubber coated neodymium magnets here!
See all of our rubber coated neodymium holding magnets here!
Fosfaterad   1-3µm Silver gray
  • Rare treatment and is done where the magnet is in eg lubrication/oily systems (eg motor/pump), where oil dissolves other surface treatments. The oil then protects the magnet against corrosion.
  • The magnet must be kept in vacuum throughout the process from fabrication to assembly to be insulated against oxygen.
NPM - North Pole Marked - A marking on the North pole of the magnet - does not affect tolerance
SPM - South Pole Marked -A marking on the South pole of the magnet - does not affect tolerance

Nickel
Zinc
Epoxy Gold
Rilsan Rubber coated

 

 
 

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