Coating of magnets

Coatings / Alloys on magnets neodymium or ferrite

Overview of the different coatings

  1. Coatings of neodymium magnets:
    a) Nickel (Ni-Cu-Ni)
    b) Gold (Ni-Cu-Ni-Au)
    c) Chromium (Ni-Cu-Ni-Cr)
    d) Copper (Ni-Cu)
    e) Epoxy resin (Ni-Cu-Ni-Epoxy)
    f) Zinc (Zn)
  2. Special coatings
  3. Pot magnets
  4. Ferrite magnets: without coating
1. Neodymium magnets (strong permanent magnets, so-called super magnets): coating required

Neodymium (Nd) is one of the rare earth metals and is used in the form of neodymium-iron-boron. It has only limited resistance to corrosion, reacts with oxygen and oxidizes very quickly if left untreated. Therefore, all neodymium magnets in our shop are provided with a coating that serves as protection. The protective layer is so thin that the type of coating has no effect on the adhesion.  
Neodymium magnets

Coatings of neodymium magnets:

a) Nickel (Ni-Cu-Ni)
  • Most common coating for neodymium magnets
  • Colour: silver, satin finish
  • Good price / performance ratio
  • Total coating thickness: approximately 12 microns
b) Gilding (Ni-Cu-Ni-Au)
  • Wafer-thin layer (24k) over the normal Ni-Cu-Ni layer, hence the same characteristics
  • Colour: gold, shiny
  • Gold plating thickness without Ni-Cu-Ni: 0.05 microns
  • Total coating thickness: approximately 12 microns

The gold plating wears off quickly with frequent use, so it is only suitable for decorative purposes, not for play or work.

c) Chromium (Ni-Cu-Ni-Cr)
  • Better resistance to abrasion and pressure points (that's why we use this coating for our sphere magnets)
  • Colour: dull, grey-metallic
  • Total coating thickness: approximately 15 microns
d) Copper (Ni-Cu)
  • Colour: shiny gold, brown-red-gold. The color can change over time due to oxidation (darkening, spots)!
  • Slightly weaker abrasion and impact resistance than Ni-Cu-Ni
  • Slightly weaker corrosion resistance than Ni-Cu-Ni
  • Total coating thickness: approximately 10 microns
  • The copper-colored surface will wear down with frequent use (like the gold-plated magnets) and is therefore only suitable for decorative purposes.
e) Epoxy resin (Ni-Cu-Ni-Epoxy) (Colloquially just called epoxy)
  • Color: Black
  • Almost 100% corrosion resistant if the coating is intact
  • Not impact resistant (crumbs easily)
  • Total coating thickness: approximately 10 microns
  • Even the smallest damage to the coating, invisible to the naked eye, will damage the magnet over time when exposed to moisture.
  • Excellent climate and saltwater resistance
f) Zinc (Zn)
  • Colour: dull gray / bluish
  • Zinc only without Ni-Cu-Ni
  • More susceptible to corrosion than Ni-Cu-Ni
  • May leave black residue
  • Total coating thickness: approximately 4 microns
2. Special coatings:

There are also other coatings for neodymium magnets, but you will only find some of these in our standard range.

uncoated

  • Colour: black/grey
  • pure magnetic material
  • Oxidation occurs and the magnets decompose in a short time when they meet oxygen and water
  • Therefore, these magnets must be quickly installed airtight and watertight
  • In general, we cannot recommend installing uncoated magnets.
Silver (Ni-Cu-Ni-Ag)
  • Colour: shiny silver
  • thin layer over the Ni-Cu-Ni layer, so the same features apply here
  • there is a purely visual difference
  • Material: Sterling Silver
  • Thickness: approx. 12 µ
Teflon (polytetrafluoroethylene)
  • Colour: grey/anthracite
  • pure Teflon without Ni-Cu-Ni
  • Extremely resistant to all acids and bases, alcohols, ketones, petrol, oils, etc.
  • not resistant only to sodium
  • very abrasion resistant
  • Total coating thickness: 12-25 microns

Magnets with a Teflon coating in our shop: Teflon

3. Pot magnets

Unless otherwise stated, neodymium magnets with a Ni-Cu-Ni or zinc coating are used here. Furthermore, in the description of the item here, "coating" means that the steel pot that sits around the magnets is coated. Very often nickel (Ni) is used here, all painted pot magnets are additionally powder-coated.
Pot magnets

4. Ferrite magnets (so-called raw magnets): no coating

Ferrite magnets can be provided with various coatings. However, this is very complex in terms of production technology and therefore expensive - the coating costs would be far higher than the actual price of the magnet.
There is a weather resistance, so there is usually no need for a coating. Therefore, our ferrite magnets are only uncoated in the program.
Ferrite magnets



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