Chrome coating is one of the most common surface treatment techniques, also name chrome plating. We use it to improve the appearance and durability of objects made from a variety of materials, including metal, plastic, and wood. You can easily notice their common applications on automotive and motorcycle parts, such as wheels and trim, as well as on household and industrial products, such as faucets and appliances. 

Chrome coating for neodymium magnets is a technique to apply a thin layer of chromium onto a neodymium magnet. And a neodymium magnet with a highly glossy surface is very likely to be with chrome plating. And the major purpose is to protect the neodymium magnet from corrosion and wear.  

The most common method is to use a technology known as electrocoating – which uses electricity – to deposit chromium layers onto the surface of a workpiece. And the chromium layers that can be less than 0.025 mm (0.001 inch).  

Basics of chrome coatings

One of the main advantages of chrome coating is its ability to resist corrosion. This makes it ideal for protecting neodymium magnets, which tend to corrode quickly in a wet working environment.  

It is also highly durable and able to withstand wear and tear, making it suitable for uses like neodymium magnet balls – you may touch them quite often to build different patterns.  

However, chrome plating can be brittle and may chip or crack if it is subjected to heavy impacts or abrasions.  

Overall, chrome coating is a good choice for neodymium magnets due to its combination of appearance, durability, and corrosion resistance. 

Applications of Chrome coating

Besides neodymium magnets, chrome plating also has a wide range of applications of products and industries, thanks to its combination of appearance, durability, and corrosion resistance.  

Some common applications for chrome coating include: 

• Automotive and motorcycle parts:  often used on wheels, bumpers, and trim for cars, trucks, and motorcycles.
• Home appliances: It is often used on household appliances, such as refrigerators, ovens, and dishwashers, to improve their appearance and durability.
• Industrial equipment: Chrome coating is often used on industrial equipment, such as conveyor belts, pumps, and valves, to improve their appearance and reduce wear and tear.
• Medical equipment: Chrome coating is often used on medical instruments, such as scalpels and forceps, to improve their durability and sterilizability.
• Furniture and decorative items: Chrome coating is often used on furniture and decorative items, such as lamps and figurines, to improve their appearance and durability.
• Sporting goods: Chrome coating is often used on sporting goods, such as golf clubs and ski poles, to improve their appearance and durability.
• Marine equipment: Chrome coating is often used on marine equipment, such as boat trailers and propellers, to improve their appearance and resistance to corrosion.

Features of Chrome coating

Osenc is able to offer neodymium magnets with several types of surface treatment. Some look similar, but actually, they have different features worth mentioning. There are several key features that distinguish chrome coating from other types of coatings, such as nickel and zinc: 

• Appearance: It is known for its high-shine, reflective appearance, which makes it popular for use on automotive and motorcycle parts and other decorative items. And it is worth considering if your neodymium magnets are for decorative purposes.
• Durability: Highly durable and able to withstand wear and tear, making it suitable for use in high-stress applications.
• Corrosion resistance: Highly resistant to corrosion, making it ideal for use in outdoor and marine environments.
• Sterilizability: It is resistant to bacteria and other microorganisms, making it suitable for use on medical instruments and other equipment that requires sterilization.
• Adhesion: Has good adhesion to a variety of substrates, including metal, plastic, and wood.

Types of chrome coating techniques

There are several types of chrome coating, including: 

Electroplated chrome 

Electroplated chrome is a type of chrome coating that is applied to the surface of an object by means of an electrical current. Electroplated chrome is known for its high-shine appearance and good adhesion to a variety of substrates. 

Vacuum-deposited chrome  

Vacuum-deposited chrome is a type of chrome coating that is applied to the surface of an object by means of a vacuum chamber. Vacuum-deposited chrome is known for its high-quality appearance and good adhesion to a variety of substrates. 

Thermal spray chrome 

Thermal spray chrome is a type of chrome coating that is applied to the surface of an object by means of a high-velocity flame. Thermal spray chrome is known for its good adhesion and high-temperature resistance. 

PVD (Physical Vapor Deposition) chrome 

PVD chrome is a type of chrome coating that is applied to the surface of an object by means of a physical vapor deposition process. PVD chrome is known for its high-quality appearance and good adhesion to a variety of substrates. 

Powder-coated chrome 

Powder-coated chrome is a type of chrome coating that is applied to the surface of an object by means of a powder-coating process. Powder-coated chrome is known for its high-quality appearance and good adhesion to a variety of substrates. 

The process

Chrome coating is offered through two main processes: hexavalent chromium coating and trivalent chromium coating. 

• Hexavalent chromium coating is a traditional form of chrome coating and is mostly used for functional purposes.
• Trivalent chromium coating is the eco-friendly solution to the traditional chrome coating option and uses chromium sulfate or chromium chloride as key ingredients in replacement of chromium trioxide.

Hexavalent chromium 

Hexavalent chromium coating, we also call hex-chrome, Cr6+, and chrome (VI) coating, uses chromium trioxide (also known as chromic anhydride) as the main ingredient.  

Hexavalent chromium coating solution is used for decorative and hard coating, along with bright dipping of copper alloys, chromic acid anodizing, and chromate conversion coating. 

Disadvantages 

From the point of view of health, hexavalent chromium is the most toxic form of chromium. For this reason, Osenc doesn’t recommend using this coating technique.  

Trivalent chromium 

Trivalent chromium coating, also known as tri-chrome, Cr3+, and chrome (III) coating, uses chromium sulfate or chromium chloride as the main ingredient. 

Advantages 

The functional advantages of trivalent chromium are higher cathode efficiency and better throwing power, which means better production rates. 

From the point of view of health, trivalent chromium is intrinsically less toxic than hexavalent chromium. Because of the lower toxicity it is not regulated as strictly, which reduces overhead costs.  

Decorative vs hard chrome coating

Chrome coating is often categorized as either decorating or hard, depending on the thickness of the chromium layer it’s used to create.  

Decorative chrome coating 

Decorative chrome coating typically ranged from just 0.05 to 0.5 micrometers thick. It’s used on workpieces and objects made of a variety of materials, some of which include aluminum, low-carbon steel, high-carbon steel, plastic, copper, and various alloys. 

• Improved appearance: Decorative chrome coating provides an appealing shine and smooth, sleek surface. When used on neodymium magnets as consumer products, decorative chrome coating can increase their perceived value.
• Corrosion resistance: Decorative chrome coating protects neodymium magnets from corrosion due to chemicals or other oxidizing agents.
• Easy cleaning: Due to its corrosion resistance, decorative chrome coating is easy to clean with household cleaners and chemicals. Its smooth surface also does not trap dirt and dust particles, so products with decorative chrome coating can continue to shine for long-term use.
• Some wear resistance: Decorative chrome coating can increase the strength of a product to some degree. However, because it is so thin, it is also fairly easy to damage.

Hard chrome coating 

Hard chrome coating is substantially thicker. It’s typically preferred because of its increased strength and durability. With greater thickness, hard chrome coating allows for the production of a strong and durable outer layer that’s naturally protected against degradation. 

• Superior hardness: Hard chrome coating is harder than most other industrial abrasives and metallic coatings, measuring between 68 and 72 HRC. 
• Durable thickness: Depending on the specific application, it is possible to apply hard chrome coating in various thicknesses to meet the project needs. Hard chrome coating between 10 and 500 micrometers will provide a hardness of about 68 to 69 HRC. It offers excellent resistance to abrasion and wear to extend component lifespan.
• Low deposition temperature: Applying hard chrome coating at low temperatures ensures the physical and mechanical properties of the substrate remain unaffected during the coating
• Wide range of bases: Hard chrome coating can apply to a wide range of base metals to suit various industrial applications – stainless steel, alloys of copper, aluminum, titanium, bronze, brass, and nickel. 
• Excellent adhesion: Offering long-term durability, hard chrome coating has excellent adherence to many substrates with minimal risk of flaking. 
• Low friction: Hard chrome coating creates very little friction when in contact with metals, graphites, carbons, and polymers.
• Wear and abrasion resistance: Because of its hardness and low friction, hard chrome coating is exceptionally resistant to wear. 
• Corrosion resistance: Hard chrome coating is a poor corrosion protector. It only gives approx. 48 hours in NSST (neutral salt spray testing).

Above is a brief introduction to chrome coating for neodymium magnets. Feel free to contact Osenc if you need help with customer neodymium magnets.