China Neodymium And Ferrite Magnets Manufacturer & Supplier 
NdFeB magnet is a strong magnetic material, it consists of neodymium, iron and boron elements, unlike ferrite permanent magnets, NdFeB magnet contains iron in its main component, so without surface protection, it will rust easily.
Generally speaking, if NdFeB magnets are exposed to a humid environment without surface treatment, they may begin to show signs of oxidization and rust within a few days to a few weeks, depending on the humidity and oxygen content of the environment.
The picture is a miniature neodymium circular magnets with a coating
To prevent NdFeB magnets from rusting, a common method is to provide a protective coating through plating. Plating can be chosen from nickel, zinc, epoxy, etc. to provide a protective layer against corrosion and abrasion. Different plating materials have different effects on the performance and appearance of the magnets, and thicker plating layers usually provide better protection.
However, even after plating, rusting may still occur if the plating layer is damaged or if the magnet is exposed to a humid environment for a longer period of time. Therefore, in order to protect NdFeB magnets, it is necessary to regularly inspect their surface condition and take appropriate protective measures, such as replenishing the plating layer or using a rust inhibitor.
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