Not every plating process is suitable for every part. This webpage explains the circumstances under which it is sensible to select the Electroless Nickel Plating process for a part.
Parts With Blind Holes and Internal Bores
A conventional plating process such as electrolytic nickel plating is very difficult to get into the recesses of parts with blind holes, as current density will be significantly lower at the edge of the recess than at the work surface. Thus, less nickel will be deposited at the recesses than at the edges. In contrast, an electroless nickel plating process deposits a consistent amount of nickel at all points on a part surface, thus, providing the best coverage into recessed areas.
When Tolerances Leave No Room for Grinding
Electroless nickel deposits to a consistent thickness. As a rule of thumb, the thickness of the deposit can be calculated on the basis of the plate time and the deposit rate for that particular bath. Typically, a deposit of 12-25 microns per hour is achieved. Therefore, it is possible for the coating thickness to be specified in the part drawings, eliminating the need for post-plate grinding to achieve the required dimensions. This is especially critical for very tight-tolerance components.
Chemical Environments Rather Than Abrasive Wear
Hard chrome is more suited to severe abrasive sliding wear, but for chemical immersion duty, hard wear resistant coatings such as electroless nickel are more suitable.
For Electroless Nickel Plating, see https://www.poeton.co.uk/surface-treatments/plating/electroless-nickel-plating/.
Aluminium and Difficult-to-Plate Substrates
Aluminium and Difficult-to-Plate Substrates. It is often wrongly assumed that all parts are suitable for conventional plating processes such as rack or barrel, using processes based on Rack and Barrel Electroplating. This is not true. Parts made from Aluminium, or from plastics, and some from composite materials can present major problems.
One Coating for Both Hardness and Corrosion Resistance
The surface hardness of mid-phosphorus Electroless Nickel (such as 6% to 9% phosphorus) is around 550 to 600 HV, with good corrosion resistance as well. So it’s a great one off coating for surfaces that are subject to abrasion and chemical attack.
Regulated Food and Pharmaceutical Applications
This surface is smooth and non-porous, preventing bacterial harbour and ensuring that cleaning agents used within processing environments do not react with the coating.
Electroless nickel is worth specifying in the design phase of your components. It is much easier to specify and produce components with the correct coating and finish, rather than retrofitting afterwards.
