I. What is magnet plating?SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
Magnet coating is used to reduce the susceptibility of magnets to corrosion and other negative environmental factors that may degrade the magnets. Powerful magnet coating is similar to ordinary paint, except that tiny particles of iron powder are mixed in. Rare earth magnetic coating materials include nickel, copper, chromium, gold, black zinc, epoxy resin, etc. The magnet coating is very thin, so it has almost no effect on the magnetic properties of the magnet itself. #strong magnetsSourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
Second, why and when do magnets need coating?SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
The surface treatment of NdFeB is not to enhance its performance, the surface coating of NdFeB magnets mainly plays a protective role. Without surface coating, NdFeB magnets can easily react with oxygen in the air and oxidize quickly, so to prevent this, we usually do electroplating treatment. And the appearance of the magnets after plating is more beautiful.SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
3、What are the common magnet plating in the market?SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
There are many different magnet coatings for sintered neodymium magnets, but the right coating will depend on the parameters of the application, and many other factors such as environment, temperature, durability, etc.SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
Common coatings.SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
1. NickelSourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
Nickel is the most common coating on powerful magnets. Nowadays, it is usually coated with three layers, i.e. nickel-copper-nickel. It protects the rare earth magnets from chipping and corrosion in the ambient air. However, it cannot be used as a protective coating against moisture, water or salt water. The nickel coating is also a decorative finish with a shiny appearance similar to the color of stainless steel. It has a thickness of 15-25 um and a working temperature of about 200°C.SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
The main application areas for nickel plated NdFeB magnet coatings are electric motors, medical devices, generators, pumps, sensors, automobiles, and several other industries.SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
2. ZincSourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
Zinc coating provides good adhesion and you can watch out for magnets in electric motors, many of them are zinc coated, which is used to protect the magnet from corrosion in the surrounding air and provides mild protection against moisture, water or salt water. However, it is not a suitable choice if the magnet is in a humid environment. It is available in thicknesses of 4-10 um and has a maximum operating temperature of approximately 120°C. The zinc coating is mainly used for low temperature applications and where a little protective barrier is required.SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
3. Epoxy ResinsSourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
Unlike gold, zinc and nickel, the epoxy magnet coating serves as an excellent barrier to salt, ambient air, water or moisture. However, it is slightly more expensive than the first three alternatives. Although it scratches easily and is 15-30 um thick, it has excellent adhesion to steel with magnetic adhesive. Epoxy coatings are mainly used in the marine, motor, sensor, automotive and consumer goods industries.SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
4. Gold PlatingSourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
Gold plated coatings are used as an FDA approved medical coating for in vivo use, and it is used as a base coating for Ni-Cu-Ni. Like the nickel coating, it helps protect the magnet from corrosion in ambient air, but can also provide mild protection against moisture, water, or salt water. Gold is very thin (about 0.1-1um), so it can perform poorly in salt spray tests, as most gold coatings are intended to be thin. Its maximum working temperature is about 200°C.SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
5. Injection molding/plasticSourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
This coating requires molds and tools. It is an excellent protective layer for rare earth magnets against breakage, impact and corrosion. It can be used for coating medium to large magnets. Please note that small magnets should not be coated with plastic. They can be used as a good protective coating against salt, moisture or water.SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
Plastics can be colored to almost any color. The common thickness of the coating is between 1 and 2 mm. The maximum working temperature usually depends on the type of ABS plastic selected. It is used in medical, educational, consumer products, etc.SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
To summarize.SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
The coating of NdFeB powerful magnets has two main functions: protection of the magnet and aesthetic appearance. But it can't change the magnet's magnetic property, it will improve the durability. Common coatings: nickel plating, zinc plating, gold plating, degree epoxy resin, injection molding/plastic, of course there are other coatings, later we will slowly take you to understand.SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
SourceRare earth magnet-https://www.rare-earthmagnet.com/magnet-plating/
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