Electroless Nickel Plating

Electroless nickel (EN) is an autocatalytic plating process that deposits a nickel-phosphorus alloy without the use of electrical current. Because the deposition is driven by a chemical reaction rather than current density, the coating builds up uniformly across all surfaces — including recesses, holes, and complex internal geometries that are difficult or impossible to plate uniformly by conventional electroplating.

The phosphorus content of the deposit can be varied to tailor coating properties. Low-phosphorus deposits offer the highest hardness and are used where wear resistance is the primary requirement. Medium-phosphorus provides a balance of hardness and corrosion resistance. High-phosphorus deposits offer the best corrosion resistance and are often specified for chemical processing and demanding environments.

After plating, electroless nickel can be heat treated to further increase hardness — up to approximately 70 HRC — making it one of the hardest commercially available coatings. Electron Plating III processes parts to MIL-DTL-26074, and can perform hardness testing and thickness verification per customer requirements.