Electroless Nickel

Electroless nickel plating is an autocatalytic process that deposits a nickel-phosphorus or nickel-boron alloy onto a solid surface via chemical reaction, without electricity. Its primary purpose is to enhance a product’s corrosion and wear properties; it also improves solderability and lubricity.

Electroless nickel is distinctive in that it deposits with exceptional uniformity, regardless of the surface. This is in marked contrast to electroplating, which is vulnerable to uneven depositing due to flux-density issues. Although the receiving surface for electroless nickel is usually aluminum, steel, copper, brass, titanium, or zinc, it can, with the appropriate catalyst, be plated onto plastics and other non-conductive substrates. For many applications, it is an excellent replacement for chrome.

Electroless nickel has evolved substantially over time. Today’s best formulas have greatly improved brightness, hardness, and adhesion properties, as well as process advantages (fast plating rate, high bath stability, long bath life) that make it easier and more efficient to run.

Electroless Nickel Processes

NBB Electroless Nickel – this process is bright and robust despite being free of lead and cadmium. It is a mid-phos process in the range of 6 to 8.

KTY Electroless Nickel – from the research labs of Uyemura-Japan, this process is the world’s first “heavy metal –free” EN. Lead, cadmium and other heavy metals traditionally used for adding brightness and stability have been eliminated.

Electroless Nickel Process for Aluminum

The ANP Electroless Nickel process substantially improves plating onto aluminum. Plating electroless nickel on aluminum has been problematic and costly due to short bath life. A normal EN bath can plate steel for six to eight MTOs (36 - 48 g/l nickel plated). Plating into aluminum reduces that bath life by about 50%. The typical failure is poor adhesion of the nickel to the aluminum, resulting in blisters or nickel peel when the aluminum is bent.

Technology developed to address this problem of short bath life used an alkaline nickel strike after zincating and prior to the regular plating bath. Drawbacks to that approach include extra tanks, process steps, and control over an additional plating bath. Failures have also been seen with nickel-to-nickel bonding.

A further application-specific problem is that strike baths always deposit magnetic nickel, thereby limiting their use to applications where magnetism is not a factor.

Uyemura’s electroless nickel for aluminum provides excellent adhesion through at least six MTOs. It does not employ a strike and adds no additional steps compared to normal aluminum preparation double zincating.

This important development uses Uyemura’s lead and cadmium-free electroless nickel in concert with proprietary cleaning, etching and zincating technologies.

ANP1012 electroless nickel plates nickel phosphorus alloys in the range of 10-12 weight percent phosphorus. It's ideal for applications requiring:

  • A high degree of corrosion resistance
  • A non-magnetic nickel finish
  • Excellent wear resistance and a low contact friction finish

ANP1012 has excellent capacity to plate aluminum alloys with good adhesion using conventional zincate pretreatment practice.

ANP and ANP1012 electroless nickel processes are RoHS compatible. They were developed by the Uyemura Tech Center, Southington, CT.