Many different coatings prevent corrosion on Neodymium magnets, but the prevalent ones are nickel, nickel-copper, and zinc.
However, the following are some of the most effective coatings along with their characteristics:
- Nickel Copper Nicker (Ni-Cu-Ni)
The most common coating is nickel copper nickel, a silvery-white metal made from iron and carbon.
It’s a relatively soft metal but strong and resistant to oxidation. Besides, it’s electric, and heat conductivity is also good.
Nickel copper nickel coating has a shiny metallic color and thickness of 12 micrometers, and its widely used for coating neodymium magnets and electroplating applications due to its reasonable price-to-performance ratio.
- Epoxy resin (Ni-Cu-Ni-Epoxy)
Epoxy coating is also very durable and can be applied in multiple layers for extra protection from the elements.
This coating is excellent for outdoor applications with lots of moisture around!
The coating is thick—about 10 micrometers—and black.
However, it’s not shock-resistant and will crumble quickly.
So, moisture can cause long-term damage to the neodymium magnets if the coating is damaged.
- Gold-coating (Ni-Cu-Ni-Au)
Some Neodymium magnets are coated with gold to protect them from corrosion, oxidation, and rust, as it is one of the least reactive elements on the periodic table.
A layer of gold-plated nickel makes up this coating, which has a shiny metallic and is usually about 12 millionths of a meter thick.
However, there are a few disadvantages. The gold is costly and rubs off easily with frequent use. Consequently, exposing the neodymium magnets to moisture and oxygen.
Chrome is used to coat Neodymium magnets to prevent corrosion because it resists rubbing and pressure and is easy to apply. Besides, it also protects from oxidation and rusting.
Chrome coating has a dull, grey-metallic color and a thickness of approximately 15 micrometers.
Due to the above properties, Chrome coating is the best choice for sphere neodymium magnets.
Copper (Ni-Cu) is also used to coat Neodymium magnets to prevent corrosion.
However, it has slightly lower rubbing, impact, and corrosion resistance than a nickel.
The thickness is 10 micrometers, and the color is shiny brown-red-gold. However, the color can change over time due to rust.
The copper-colored surface rubs off easily, just Like gold-coated neodymium magnets, so they’re only meant for decoration.
ABS Plastic can also be used for coating neodymium magnets because it can withstand high temperatures and is highly corrosion-resistant. This coating serves the aesthetic purpose as it is available in multiple colors.
The ABS plastic coating requires an injection mold to be created to encase the neodymium magnet. Moreover, the coating is usually thicker than other coatings to ensure plastic flows easily during injection molding.
Zinc can also be used as a coating for neodymium magnets because it’s resistant to corrosion, which will help preserve the neodymium magnet’s integrity over time. Its self-sacrificing property creates a durable layer of protection around the neodymium magnets by oxidizing the outer layer of coating.
It also helps keep the neodymium magnet from attracting dirt or other particles that might otherwise interfere with its performance.
Teflon is also used to coat neodymium magnets as it is durable, corrosion-resistant, resilient to the harsh environment, and protects the neodymium magnet from exposure to moisture and oxygen. Like ABS Plastic, Injection molding is also used for Teflon to encase the neodymium magnets.
Teflon is also because it has a low coefficient of friction, which means that it doesn’t stick to other materials very well. That makes it a good choice for coating neodymium magnets because it prevents them from sticking to other objects.
The soft but stretchy quality of rubber makes it a good choice for coating neodymium magnets. That helps protect the neodymium magnets from being damaged, oxidized, corroded, and rusted and keeps them from sticking to each other.
Titanium is used for coating neodymium magnets because it forms a tough skin that resists oxidization, rusting, corrosion, and scratching and chipping. It also has a low friction coefficient, which helps to reduce wear and tear on the neodymium magnet.
The primary reason tin is used for coating neodymium magnets is its low oxidation rate. It also has a low melting point, making it a good conductor of electricity and corrosion-resistant.
Additionally, tin has a low “Coercivity,” meaning it can be easily demagnetized. This quality makes it ideal for use in coatings, as it allows the neodymium magnet’s full magnetic force to be achieved without any hindrance.
The titanium nitride coatings improve the neodymium magnets’ resistance to oxidation, corrosion, and scratching, which can prolong their useful life.
Everlube is a trademarked name for a range of lubricating and corrosion-resistant coatings. It is also known as dry film lubricants. It is often used to coat neodymium magnets because it protects them from corrosion and helps keep them running smoothly.
- Polytetrafluoroethylene (PTFE)
PTFE, or Polytetrafluoroethylene, is a synthetic fluoropolymer used as a coating material because of its non-stick and low friction properties.
It is most commonly used in kitchenware (e.g., baking pans), cookware, and other household items.
PTFE has also been effective as a coating for neodymium magnets. It can help prevent the accumulation of corrosion and oxidation on the surface of the neodymium magnet.