Electroless Nickel Plating

Electroless Nickel Plating - Micro Crystalline to Amorphous Hard Nickel Phosphorus Coating

Electroless Nickel plating (EN), also known as autocatalytic nickel, is a micro crystalline to amorphous, hardenable nickel-phosphorous alloy coating. It offers a good barrier coating corrosion resistance. Electroless nickel is generally applied to a thickness range of 25 to 150 microns (0.0001” to 0.0015”) typically does not require further surface finishing, machining or grinding after plating.

The autocatalytic reaction between nickel and reducing agent in the plating bath deposits nickel onto metal substrates without the use of anodes and electrical current, hence the name “electroless”. Since no high or low current densities exist, a very uniform thickness of deposits over irregular shapes can be achieved.

Phosphorous content in the coating can range from 5% to 12%. U.S. Chrome offers “Mid-Phos” (5% to 8%P) and “High-Phos” (10% to 12%) electroless nickel plating services.

Electroless nickel can be heat treated at relatively low temperatures (400° to 450°C) to achieve higher hardness (up to 1000 HVN); however, corrosion resistance is reduced.

For many applications electroless nickel plating is applied as a barrier coating under Hard Chromium to provide the ultimate in corrosion and wear resistance.

Features & Benefits

Medical device plated with a duplex coating of 0.0003 electroless nickel and 0.0003 hard chromium.

Electroless Nickel Plating Properties Hardness varies from 500-600HV(as plated) to 850-950HV (after heat treatment) depending on phosphorous content. Usual Temperature Limitation of 1000 degrees F 540 degrees C Download (PDF)