Harsh environments with humid conditions may arise due to latitudinal location or because of more localised influences such as seaside locations, proximity to sea breezes or constant exposure to weather. Choosing the right magnet (or coating) can overcome these conditions and reliably perform to a high standard.
In high humidity atmospheric conditions, standard nickel-coated Neodymium magnets will eventually succumb to corrosion and will stop performing at an acceptable level. Ferrite or Samarium Cobalt magnets may be viable alternatives. Ferrites and Samarium Cobalt magnets have excellent resistance to corrosion and will largely remain unaffected by moisture and humidity.
A larger size Ferrite or Samarium Cobalt magnet may need to be applied to compensate for its relatively weak holding power. In other situations, where using a larger Ferrite or Samarium Cobalt magnet is not possible because of space restrictions, a strong Neodymium magnet with a protective coating may prove to be a suitable alternative.
AMF supplies Neodymium magnets with Teflon, Epoxy and Plastic coatings which provide improved resistance to the effects of humidity. It should be noted that additional coatings of any kind have a negative impact the strength of a magnet because of the 'gap' created between the magnet and the metal surface.