What Engineers Should Know about Zinc-Nickel Coatings
What is Zinc-Nickel Plating?
To best understand what a Zinc-Nickel coating is, we’ll first address a common misconception about what it is not.
Zinc Nickel plating is NOT a layer of Zinc Plating followed by a layer of Nickel Plating
(Or Nickel over Zinc).
We do not plate one finish over the other.
Zinc-Nickel coating is an alloy, meaning Zinc and Nickel co-deposit on the surface of a steel substrate to prevent it from rust and corrosion.
The combination of Zinc and Nickel creates a unique composition that will corrode slower than Zinc alone.
With a makeup of approximately 10-15% nickel and the remainder zinc, this alloy coating can provide up to ten times the protection of conventional zinc plating.
The Plating Process for Zinc-Nickel Plating
Zinc- Nickel is applied to metal through an electroplating process like that used for conventional Zinc.
It is a two-part process using an electrical current to apply zinc-nickel onto the parts’ surface, followed by a chromate conversion coating to passivate the zinc-nickel deposit and increase the corrosion protection. This can be done through either rack or barrel plating depending on the characteristics and durability of the part.
The plated Zinc-Nickel finish provides a thin coating to the parts’ surface that is hard, smooth, and consistent which provides key benefits including:
- Superior corrosion protection
- Better wear resistance to moving parts (compared to conventional zinc and other finishes)
- Better performance under thermal stress
Color and Appearance of Zinc-Nickel
The color and appearance of a part after plating depends on which Zinc-Nickel finish is specified and can vary depending on the type and condition of the base metal.
Trivalent Zinc Nickel – Offers a distinct blue appearance
Hexavalent Zinc Nickel – Offers an iridescent finish with dominant yellow, red and green tones.
Black Zinc Nickel – offers a satin black finish
Is Zinc-Nickel Expensive?
Zinc-Nickel is typically more expensive than conventional Zinc when comparing upfront costs. However, the increased costs are often nominal in relation to the amount of additional corrosion protection and improved durability the coating provides.
For components that need maximum protection to extend the lifespan of a product, Zinc-Nickel can provide tremendous value.
Who is using Zinc-Nickel?
The use of Zinc-Nickel has increased across industries, especially among automotive and aerospace applications. With extended product warranties, longer life cycle requirements, more stringent safety standards and reduction of environmental impact companies need higher corrosion resistance.
Zinc-Nickel is also used as a suitable alternative to Cadmium Plating, a common finish utilized in highly-corrosive environments. Cadmium plating has been phased out due to its environmental concerns, and for many companies has been effectively replaced by Zinc-Nickel.
Zinc-Nickel Product Applications
Zinc Nickel is used in a wide variety of applications including:
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Automotive |
Engine Components exposed to high temperatures Undercarriage components exposed to salt and elements
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Oil & Gas |
Large Fasteners
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Marine |
Components with constant exposure to humidity and salt.
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Agricultural |
Components with exposure to fertilizer chemicals Hydraulics
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Heavy Equipment |
Components exposed to the elements Hydraulics
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Railroad |
Safety components for railcars Fasteners
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Structural |
Bridges Building components Outdoor structures Playground equipment
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Utilities |
Powergrid components
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Telecommunications |
Electronic enclosures Outdoor components Cable Tray
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Renewable Energy |
Batteries Power generation
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Military |
Hydraulic Electronics |
For an in-depth look at what zinc-nickel is, how it protects, where it is used, and further misconceptions surrounding the finish, read our article that was featured in Machine Design Magazine.