Zinc nickel plating is used where corrosion resistance and durability are critical. It is selected for parts that will be used in harsh environments, such as in automotive, aerospace, and industrial applications. Learning about the various steps involved in the process helps to explain why zinc nickel plating provides such reliable and consistent protection.
Surface Cleaning and Preparation
The process starts with cleaning. The components must be cleaned to remove any oils, greases, dirt and surface contaminants that would prevent the coating from adhering to the substrate. Cleaning stages are often implemented to achieve the best possible cleaning of the component, ensuring it is chemically clean prior to coating.
Activation and Electroplating
After cleaning, components undergo an activation step in a mild acid solution to remove any oxide layers from the metal. The components are then soaked in an alkaline electrolyte where zinc and nickel ions are simultaneously reduced to form a uniform alloy coating.
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Rinsing and Conversion Coating
Following plating, the components are rinsed multiple times to remove any solution residue and to minimise the potential for contamination. A chromate conversion coating is applied to the part to provide additional corrosion protection and to enhance the overall stability of the surface.
Baking and Final Inspection
High strength steel components can be baked to mitigate hydrogen embrittlement risk. Optional sealers can be applied for harsh use cases. Final inspection checks thickness, tackiness, and surface quality.
