The most common coating for Neodymium magnets is Nickel + Copper + Nickel (Ni + Cu + Ni). This coating offers the magnet relatively good protection from corrosion and passive applications. If the magnet will be exposed to moisture or liquid then consider the use of an organic coating such as Epoxy. A hard wearing coating, Epoxy is suited to applications where the magnet will come under some friction or knocking.
Plating / Coating Options
The following is a list and description of available coating options for custom magnets. Note: Magnets can only be electro-plated before magnetization. if the plating is compromised after magnetization via abrasion or deliberate machining they cannot be re-plated. Some coatings such as plastic may be done after magnetization, If the process does not exceed the magnets maximum operating temperature.