Neodymium (NdFeB) magnets corrode quickly if left bare, because the iron content reacts with moisture in the air. In almost all commercial and industrial applications, some form of coating is required.
Nickel-Copper-Nickel (NiCuNi)
The most common coating. Good corrosion resistance for indoor, dry-to-moderate humidity environments, and relatively low cost. This is the default choice for most general industrial and consumer applications.
Epoxy
Adds a non-conductive, flexible outer layer, often over a nickel base. Better protection against chemicals and mild outdoor exposure, and reduces the risk of chipping on sharp-edged magnets.
Zinc
A more economical option than nickel, with moderate corrosion resistance. Common where cost matters more than long-term outdoor durability.
Gold / PVD coatings
Mainly cosmetic or used in specific electronics and jewelry applications, applied over a nickel base for corrosion protection with a decorative finish.
For marine, outdoor or high-humidity environments, we recommend discussing the exact conditions with us before ordering — coating choice can significantly affect service life.