Moisture in the atmosphere is potentially enough to cause an uncoated NdFeB magnet to show signs of corrosion. Marine environments are particularly effective at makingNdFeB magnets corrode. The process of corrosion is similar to rusting – the structure of the Neodymium Iron Boron magnets changes permanently resulting ina progressive loss in magnetic performance (the magnet will weaken; the magnet also breaks down into a powder during the corrosion process). Total magnetic failure is possible due to corrosion. To prevent this, the magnet is given a coating / surface finish.
The standard coating is a triple layer plating of Nickel-Copper-Nickel (Ni-Cu-Ni). Unless requested otherwise, this Ni-Cu-Ni coating is always applied to the magnets. It should be noted that the level of protection given by any coating depends on the environment the magnet will be subjected to and how the coating is looked after. If the coating is scratched or broken, it will not offer protection fromvmoisture.