Will permanent magnets rust when exposed to water?
Permanent magnets rust? Yes! Although permanent magnets have strong magnetic properties, they are not “invulnerable”. Especially the common NdFeB magnets, whose main component is iron, are easily oxidized and rusted in a humid environment.
Why do permanent magnets rust?
Material composition: The main component of most permanent magnets is metal alloys, such as NdFeB, SmCo, etc. These metals are prone to oxidation reactions in humid environments, leading to corrosion.
Electrochemical reaction: When permanent magnets come into contact with water, tiny electrochemical cells are formed, which accelerate the corrosion process.
Consequences of rusting magnets:
Reduced magnetic properties: Rust will destroy the crystal structure of the magnet, causing the magnetic properties to decrease or even disappear.
Appearance damage: Rusted magnets not only affect the appearance, but may also cause the surface of the magnet to be uneven, affecting use.
How to prevent magnets from rusting?
Surface coating:
Electroplating: Plating a layer of metal such as nickel and zinc on the surface of the magnet can effectively prevent corrosion.
Organic coating: Such as epoxy resin coating, which can provide good corrosion resistance and insulation.
Passivation treatment: A dense oxide film is formed on the surface of the magnet by chemical methods to improve its corrosion resistance.
Dry storage: Store the magnet in a dry, ventilated environment to avoid moisture.
Avoid contact with acids and alkalis: Acidic and alkaline substances will accelerate the corrosion of the magnet and should be avoided.
Regular inspection: Regularly check whether there are signs of rust on the surface of the magnet and deal with it in time.
Corrosion resistance of different types of magnets：
NdFeB magnets: The strongest magnetic properties, but the worst corrosion resistance. SmCo magnets: High magnetic properties and good corrosion resistance, but the price is high. AlNiCo magnets: Low magnetic properties, but good corrosion resistance and high temperature resistance. Ferrite magnets: The lowest magnetic properties, but good corrosion resistance, high temperature resistance, and cost performance.
How to choose corrosion-resistant magnets？
According to the use environment: If used in a humid or corrosive environment, magnets with good corrosion resistance should be selected, such as SmCo magnets or specially treated NdFeB magnets.
According to the requirements of magnetic properties: If the requirements for magnetic properties are higher, you can choose NdFeB magnets and take corresponding anti-corrosion measures.
