Different Types of Coatings that are Suitable for Your Magnet
There is a wide range of protective coating selections for your magnets. However, different factors may affect your selection of the correct coating for your applications. Among the factors are FDA approval, durability, temperature, environment, and more. Here at Dailymag, we offer a wide range of protective magnet coatings that are available in different parameters. We also provide its characteristics to help you choose the right coatings.
Benefits of Protective Coating to Magnets
Corrosion Protection
Protective coating provides protection to the magnet against corrosion so it can be used for outdoor and other applications that may be exposed to corrosion, moisture, and other elements.
Cleaning Ability
If a magnet is coated with a protective layer, it can provide an easily cleanable layer. It provides the magnet with a smooth surface that allows easy debris removal.
Electrical Conductivity
Metallic protective magnet coating can affect electrical conductivity. Protective coating such as gold has more conductivity to ensure that magnets can provide effectiveness in different applications.
Physical Integrity
Magnets are prone to chipping and brittle due to impacts and mechanical stress. Protective coating provides an extra protection layer to the magnet resulting in increased physical integrity.
Nickel
- It is the most common coating used for magnets
- Comes with three layers including nickel-copper-nickel
- Protects the magnet against corrosion
- Provides light salt water, water, and humidity coating
- Offers a decorative and aesthetic finish
- Has 15 up to 25um thickness
- Low cost
- Up to 200⁰C maximum working temperature
- Magnets with nickel coating are usually used in medical devices, motors, pumps, generators, sensors, and more.
Black Nickel
- Composed of 3 layers, nickel-copper-nickel with a black finish
- Provides metallic gray or black finish
- Offers an aesthetically pleasing finish
- Requires epoxy or glue when attaching to plastic or steel
- Low-cost coating
- Provides light chipping protection
- 12 up to 25um thickness
Gold Coating
- These are approved by FDA for medical in-body use
- Ni-Cu-Ni undercoating
- Provides slight magnet protection against salt water, water, and humidity
- Offers gold finish
- Up to 1000⁰C melting point
- The gold layer has 1um thickness
- Protects the magnet from corrosion
- High production cost
- Up to 200⁰C maximum working temperature
Zinc Coating
- Provides excellent adhesion if attached to steel using epoxy or glue
- Provides magnet protection against corrosion
- Offers slight saltwater, water, or humidity protection
- Steel and magnet has less air gap due to the coating’s thinness
- Black or white-blue color
- 4 up to 10um thickness
- Zinc-coated magnets are used for low-temperature applications that require low protective barrier
Parylene
- Widely used for in-body medical coating use
- FDA-approved
- Provides transparent finish
- 120 up to 305⁰C maximum working temperature
- The production cost depends on the quantity
- Provides saltwater, water, or humidity protection
Epoxy Coating
- Provides excellent protection against saltwater and salt air
- Should be carefully handled during assembly to avoid scratches
- Using a magnet-rated glue makes allows it to provide good adhesion to steel
- 15 up to 30um thickness
- Black or white in color
- Medium production cost
- Up to 200⁰C maximum working temperature
- Epoxy-coated magnets are used for automotive, consumer products, sensors, motors, and marine
Plastic or Injection Molding
- Tooling and molds are required
- Provides magnet protection against corrosion, impact, and breakage
- Suitable for medium to large magnets
- Excellent protection against salt water, water, humidity, and more
- Available in different colors
- 1 up to 2mm thickness
- The production cost depends on complexity since tooling and molds are required
- The maximum working temperature also depends on the plastic type used
TEFLON or Molded PTFE
- Up to 250⁰C maximum working temperature
- Offers protection against autoclave, fluids, and humidity
- 5 to 3mm thickness
- Available in white color
- Industries that used Teflon-coated magnets include medical and food
- Provides superior protection to the magnets against corrosion, impact, and breakage
- Requires tooling and mold for production
- Suitable for medium to large magnets
Spray PTFE
- Food-grade coating
- Tooling is required
- Used for food and medical industries
- The mechanical hold is needed for gluing to steel or plastics
- Provides magnet protection from corrosion
- Suitable for small to large size magnets
- Medium production cost
- Available in thicknesses ranging from 20 to 25mm
- Provides protection against fluids and humidity
- Requires proper handling to avoid scratches
Rubber Coating
- Available -0.5mm thickness
- Offers superior friction when sliding against steel
- Industrial use and holding applications
- Needs tooling and molding
- Provides protection against corrosion, impact, and breakage
- Available in standard black color, however, can also be purchased in another color
- Up to 135⁰C maximum working temperature
- Suitable for medium to large magnets
Rhodium
- It is a very strong magnet coating that provides protection against tarnish and scratches
- Also offers maximum corrosion resistance
- It has a white reflective finish
- Decorative appearance
- High production cost
- 1 to 5um gold layer thickness
- Up to 2000⁰C melting point
- Magnets with rhodium coating are used for automotive, medical, and jewelry
Titanium Nitride Coating
- FDA-approved for medical use
- It’s a very hard coating with a strong magnet bond
- Environmentally-friendly
- Chemically resilient
- Smooth surface with metallic gold color
- 2 to 6um gold layer thickness
- Up to 500⁰C maximum working temperature
Copper Coating
- It is commonly used as a decorative coating
- Provides magnet protection against corrosion
- The coating can be rub off when used for a longer time
- Provides copper finish
- Available thickness ranging from 10 to 20um
- Medium production cost
- Up to 200⁰C maximum working temperature
- Mostly used in the decorative industry
Chrome Coating
- It is a decorative coating
- Also used for providing protection against corrosion
- Doesn’t provide protection against saltwater and humidity
- Offers a chrome finish
- Thickness available ranging from 12 to 15um
- Up to 200⁰C maximum working temperature
- Widely used for consumer products, cosmetics, decorative, and jewelry
Silver Coating
- A decorative coating used for decorative, jewelry, and more applications
- Providing protection to the magnet against corrosion
- Offers silver finish
- Available thickness ranging from 10 to 20um
- Low to medium production cost
- Up to 200⁰C maximum working temperature
Stainless Steel Coating
- Extremely robust
- Can withstand different environmental factors
- Offers superior corrosion resistance
- Suitable for marine, outdoor, and other harsh environments
- Provides physical impact protection
- Protection against cracking and chipping
Phosphorus Coating
- Forms an inert protective barrier
- Phosphorus-coated magnets are ideal for outdoor applications
- Used for surveillance, defense, security, and more
- Offers corrosion resistance
