Electroless Nickel

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

Roller cage plated uniformly on all surfaces with 0.0005 electroless nickel plating

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.

During the electoles nickel plating process, 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

  • Excellent corrosion resistance - dependent on phosphorous content 48-100 hours per ASTM B-117 are typical.
  • Durability good - but wear resistance is less than hard chromium.
  • Deposits nickel uniformly - on any part geometry due to no current density distribution inherent in electrolytic processes.
  • USC offers a proprietary method - for applying electroless nickel to aluminum alloys.

The I.D. of the housing is chrome plated 0.003

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


Typical Applications for Electroless Nickel Plating

Plastic & glass molds, bearings, gears, medical parts, oil & gas, and aircraft components.

MIL-C-26047, ASTM B733, AMS 2404