Electroless Nickel


Electroless nickel plating (EN) is an auto-catalytic reaction used to deposit a coating of nickel on a substrate such as steel, brass or aluminium.

The process relies on the presence of a reducing agent, which reacts with the metal ions to deposit metal. This alloy of nickel and phosphorous can have different percentages of phosphorous, ranging from 2-5% (low phosphorous) to up to 11-14% (high phosphorous) The metallurgical properties of the deposit depends on the percentage of phosphorous.

With electroless nickel plating, unlike electroplating, it is not necessary to pass an electric current through the solution to form a deposit. Electroless nickel plating has several advantages over electroplating. It provides a uniformly even deposit regardless of workpiece geometry.

This plating technique is normally applied to prevent corrosion and increase wear resistance.

  • Medium phosphorous electroless nickel – Medium phosphorous treatment has a high speed deposit rate and offers bright and semi-bright options for corrosion resistance and cosmetic applications.The processing is very stable and is the most common type of electroless nickel applied.
  • High phosphorous electroless nickel – High Phosphorous electroless nickel offers high corrosion resistance, making it ideal for industry standards requiring protection from highly corrosive acidic environments such as oil drilling and coal mining. With a micro-hardness ranging up to 600 VPN, this type ensures very little surface porosity where pit-free plating is required and is not prone to staining. Deposits are non-magnetic when the phosphorous content is greater than 11.2%.