This can be a difficult process to get right on Aluminium components as they require special preparation before plating to ensure the coating will bond to the component.
Why Aluminium Needs Zincate Pre-treatment
Aluminium parts are protected with a natural oxide layer. Before coating this layer needs to be removed. A zincate pre-treatment solution is used to form a zinc layer on the surface of the aluminium, which allows the nickel to bond to it. Without the zincate pre-treatment the coating would peel off.
Uniform Coverage on Complex Shapes
In addition, electroless nickel is evenly distributed over surfaces containing recesses, threads, and bores, internal or otherwise, and is therefore particularly suited to components such as aluminium castings and precision machined parts including housings.
Corrosion Protection It Actually Adds
The medium-phosphorus deposits (6 to 9% phosphorus) offer good corrosion protection to the aluminium. They also have good adhesion to the aluminium. The nickel coating will protect the aluminium from moisture and mild chemicals. This coating is very good for components that are to be used in automotive and/or marine environments.
Hardness Considerations for Softer Substrates
In comparison to steel, the aluminium component is a softer material, so the majority of wear is to to to to to be taken by the coating. Your South West Metal plating supplier can advise on whether a higher phosphorus content or indeed a post plate heat treatment is required to achieve the desired performance from your aluminium components.
Specifying Thickness Correctly
Typical coating thicknesses for aluminium components are in the order of 15-25 microns, it is then possible to machine pre-plate parts to exacting tolerances without exceeding overall dimension.
Operators in the vicinity of the plating bath must also be aware of safe handling of nickel compounds within the plating environment to comply with set exposure limits.
Getting the pre-treatment and thickness of the deposit right the first time can save a lot of time and effort.
