Zinc-Nickel for Corrosion Protection
Zinc-nickel plating is an environmentally and safer alternative to cadmium and can be used across a wide range of industries. It combines the sacrificial coating properties of zinc with the strength, ductility, and corrosion resistance of nickel – creating a surface finish that, in some cases, is superior to cadmium.
The use of sacrificial, anodic coatings has become increasingly popular in the aerospace, industrial and automotive sectors due to its corrosion protection, wear resistance and ability to limit thermal stress.
Why is zinc-nickel resistant to corrosion
Both ZnNi and Cadmium are sacrificial coatings that will corrode before the substrate material, protecting it. That is why both coatings experience discoloration before red rust appears. In ZnNi the Zn continues to act as a sacrificial coating, but in addition the Ni is able to act as a barrier layer due to being more noble than the Zn and the underlying substrate. ZnNi coatings protect best when there is between 11-16% Ni with Zn balance.
Why you should use zinc-nickel and how to properly apply it.
Watch our video that explains the benefits of Zinc-Nickel 4018 and gives a step-by-step demonstration on how to apply the solution
What applications use zinc-nickel plating?
Zinc-nickel plating can be used for a variety of applications across a wide range of industries. These include:
- Landing gears,
- Flap tracks,
Zinc-nickel plating and the aerospace and defence industry
Although an LHE zinc-nickel deposit has been available for over 20 years, it has seen a significant increase in use over the last few years coinciding with the aerospace industry’s and the environmental push to find safe and viable alternatives to cadmium coatings. Selective plating process of zinc-nickel is approved by Boeing, Goodrich, Messier-Bugatti-Dowty, Bell, NASA, Airbus, and more.
Zinc-nickel plating specifications
In addition to the numerous commercial specifications written, AMS 2451/9, Brush Plating Zinc-Nickel, Low Hydrogen Embrittlement was written to cover the requirements for brush plating zinc-nickel by electrodeposition. When tested in accordance with ASTM B 117, zinc-nickel withstands 1000 hours of exposure to salt spray corrosion with no evidence of base metal corrosion; as well as passing hydrogen embrittlement testing with notched tensile samples being subjected to a 200-hour sustained load test at 75% of the notched ultimate tensile strength. This conforms with ASTM F519 and all applicable Federal, Military, AMS, ASTM requirements.