Electroless nickel plating, or ENP as it is known, is the process of using chemical reduction to apply a nickel-alloy coating. It doesn’t use the electric current that is part of the electroplating process.
The ENP used in engineering is typically a form of nickel phosphorous deposit with between 2 and 14 percent phosphorus. The more phosphorus, the more resistance to corrosion; however, less phosphorus provides a harder result.
The ENP is applied by using chemical reducing agents such as sodium hypophosphite to reduce nickel ions into metallic nickel. It is commonly deposited at a thickness of between 25 cm and 75 cm.
Electroless nickel plating benefits
The type of ENP offered by companies such as poeton.co.uk/standard-treatments/electroless-nickel-plating/ offers corrosion protection, resisting such common corrodents as hydrogen sulphide, oxygen, carbon dioxide, and salt water. ENP with high phosphorus levels also limits the potential sites for corrosion to begin.
ENP offers superior levels of uniformity compared to electrolytic deposits, ensuring a thick and uniform coating, even inside tubing walls, holes, and slots. Even without heat treatment, it offers good levels of hardness and resistance to wear.
ENP is a cost-effective solution and can be used in a variety of applications to extend service life while lowering costs compared to alternatives such as corrosion-resistant alloys. This is particularly true when it comes to protecting carbon steel from localised corrosion and preventing weld corrosion and flange attack. You can read more about the electroless plating process on the Science Direct website.
Type of deposits
Another benefit of ENP is that the deposit’s phosphorus content can be adjusted to best suit a certain application. Add to this its ability to deposit uniformly and ENP is perfectly suited for even complex shapes that may not be fully suitable for electroplating.