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Electroless Nickel Plating

Any portion of a part that is equally wetted by the electroless nickel solution will plate uniformly including blind holes and the inner diameters of tubing or fittings.

The codeposited phosphorus in the deposit increases the lubricity over that of traditional nickel plating and the percentage of phosphorus in the coating also affects deposit properties such as magnetism, corrosion resistance and hardness. In addition, a post-plate baking at temperatures above 260C can transition electroless nickel deposits from an amorphous as-plated state to a crystalline structure, greatly increasing hardness.

Application of electroless nickel (EN) is especially suitable for complex shaped products because coating thickness can be controlled within ± 2 microns accuracy. This cannot be achieved in any electroplating process due to thickness variation resulting from non-uniform current distribution. To get a pore-free surface the coating thickness shall be at least 25 microns. Depending on the type of EN bath the phosphorus-content varies from 8 – 13%. Higher phosphorus-content gives higher corrosion- and chemical resistance of the coating, but also results in less magnetism and less solderability of the coating. With a thermal post treatment the EN-coatings can be hardened up to 1000 HV.