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Plating for corrosion protection

Corrosion Protection of Electroless Nickel Plating vs Zinc Plating

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A responsible metal finishing company would never posit that one finish is categorically better than another. The value of each plating material will depend heavily on how it is used. 

Electroless nickel plating (EN) or zinc electroplating both offer excellent corrosion protection to the substrate, but they differ in a number of other ways that will push you towards a final decision.

Zinc Electroplating Properties

Electroless Nickel Plating Properties
  • Gradually wears down. Zinc sacrifices itself over time to protect the base material.
  • Anodic to steel. When layered over steel, zinc galvanically protects it and thus can safely be a thinner plate without leading to rust through minuscule gaps in the plate.
  • Substantially less expensive than nickel plate.
  • Optimal in low to moderate corrosive environments.
  • A tough material, but less so than nickel.
  • Easy to customize and color with matte, shiny, passivated, or chromated finishes in a variety of colors (from clear to iridescent yellow or even black).
  • Difficult to achieve a consistent thickness. Prone to “dog-boning” (thicker areas around edge and convex corners and thinner around concave corners).
  • Does not wear away. Electroless nickel acts as a solid and permanent barrier. 
  • Cathodic to steel — a consistent finish is important. If there are pinholes or interruptions in the plate, underlying steel will try to galvanically protect the nickel (potentially leading to rust blooms).
  • Offers higher total corrosion resistance that is suitable to extremely corrosive applications.
  • High hardness and tensile strength.
  • Less customizable in terms of finish than zinc, but highly attractive as is, polished, or brushed.
  • The electroless process provides an unparalleled consistent and uniform finish without dog-boning.

Which Option Is the Best Plating For Corrosion Resistance?

Between the two, zinc tends to win on cost while nickel wins on finish. There are exceptions, though, such as when the chromated options for zinc are cosmetically desirable. Both offer great corrosion protection.

The key differences between the corrosion protection of electroless nickel vs zinc can be divided up like this: 

  • Electroless nickel is a more durable and long-lasting finish with higher hardness, which makes it more reliable in extremely corrosive and harsh environments. Since it’s cathodic to steel, flaws or nicks in the plate can lead to rust blooms, but it’s also a highly consistent finish so this is rarely an issue with an electroless process.
  • Zinc provides more cost-effective corrosion protection on steel substrates because it’s anodic to steel. You won’t need to worry about using a thinner plate or an inconsistent finish, since it will still galvanically protect the steel. However, it will wear down over time and is thus better for uses where there are fewer forces to degrade it or rub it off.

Talk to an Expert

Still have questions? Contact a metal finishing expert for personalized guidance on the considerations that should weigh on your choice of zinc, electroless nickel, or another plating for corrosion protection. Our team has decades of experience and a customer-centered mission. Just share the details of your plating project and we’ll help you to identify the best solution for your needs.
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