Some coatings just aren’t up to handling parts that are exposed to high heat cycling. Standard zinc plating is one of them, and in this article we take a look at the alloy of Zinc Nickel Plating and why it’s so well suited to surface protecting brake brackets, exhaust fixings and other under-bonnet fasteners.
The Temperature Range to Know
The high temperature resistance of Zinc Nickel Plating is such that it can operate continuously up to 120°C / 150°C and for short periods up to 200°C without loss of protection. In contrast, standard zinc coatings will start to degrade at temperatures of around 70°C and above.
Why Nickel Content Makes the Difference
The nickel content in the alloy, typically in the range of 12% to 15%, helps to stabilise the crystal structure of the coating. This means that unlike a pure zinc plate which can develop micro cracks in the coating as it goes through thermal cycles, the nickel in the alloy holds the crystal matrix together, thus ensuring that the coating’s adhesion and barrier properties are not compromised. For more on this, take a look at www.swmf.co.uk/surface-coatings/zinc-nickel-alloy-plating.
Parts That Commonly Specify It
These are the type of parts that are hot, and then are exposed to salt and humidity. All zinc plating is not created equal. For applications like these, a Zinc Nickel Plating is by far the better coating.
What to Check When Ordering
When ordering parts with zinc nickel plating make sure that the alloy ratio is within the 12% to 15% range. uk/){rel=”nofollow”}, especially for high-strength fasteners. uk/surface-coatings/zinc-nickel-alloy-plating/).
Getting the alloy ratio and post-treatment right at the beginning is important to prevent problems on service.
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