Electroless Nickel Plating (ENP) is the deposit of a nickel-alloy coating by chemical reduction – without the electric current that is used in electroplating processes!
In contrast to an electroplating solution, ENP doesn’t require an external source of current, it utilizes a chemical reducing agent built into the bath. The process provides a continuous build-up of deposit, since the metal being plated is itself a catalyst for the plating reaction.
Electroless Plating is metal (nickel) deposition by a controlled chemical reaction (reducing nickel ions to metallic nickel) with a chemical reducing agent such as sodium hypophosphite.
Electroless nickel plating creates a perfect, uniform anti-rust protective coat with the most common thickness between 25-75 microns, it allows ferrous substrates to withstand extreme temperatures and environments including attacks by chemicals, saltwater and abrasive substances.
The majority of ENP for engineering purposes is a nickel phosphorus deposit containing 2 to 14% phosphorus. The higher the phosphorus content the greater the corrosion resistance, however the compromise on increased phosphorus content is a decrease in hardness, which can be improved by heat-treatment.
Primary uses for Electroless Nickel Plating:
- Anti-corrosion 30%
- Wear/hardness 25%
- Magnetic properties 18%
- Deposit uniformity 11%
- Conductivity 6%
- Lubricity 5%