Electroless nickel plating:       

Electroless nickel plating, or EN for short, is the plating of a nickel-phosphorous alloy deposit onto suitable substrates using a chemical reduction process. Differing from electroplated nickel deposits, EN deposits are produced without an external electrical current. This avoids the problems associated with uneven deposit thickness or deposit uniformity due to current density issues. Therefore, EN processes produce very uniform, hard and lubricious coatings on catalytic metallic, catalyzed metallic and catalyzed non-metallic substrates. Uniform deposit thicknesses are achieved on the inside of tubes, threads, blind holes, grooves and slots. The EN deposit can contain up to 13% phosphorous by weight. A variety of unique deposit properties are obtained by varying the percentage of phosphorous in the coating deposit. Low phosphorous deposits (<5% by wt.) yield hard deposits with excellent wear resistance and good corrosion resistance in alkaline environments. Medium phosphorous deposits (5%-10% by wt.) yield deposits with high hardness and wear resistance at competitive costs. High phosphorous deposits (>10% by wt.) yield deposits that are non magnetic and highly corrosion resistant in acidic environments.

Overall features of EN include: wear resistance, excellent corrosion resistance, high hardness, low friction, availability of co-deposits, deposit brightness, deposit uniformity, chemical resistance, solderability, weldability, brazeability, ferromagnetic and non-ferromagnetic properties.