ELECTROLESS NICKEL PLATING & DIFFUSED NICKEL PLATING: WHAT’S THE DIFFERENCE?

What’s the difference between Electroless Nickel Plating and Diffused Nickel plating? Electroless Nickel Plating Technical Manager, Steve Whitehead, takes a look at the main differences between the two coatings and gives advice when each should be used.

“Firstly, it is important to understand the differences between Electroless Nickel Plating and Diffused Nickel Plating and what the properties of each are.

Electroless Nickel Plating is the deposit of a nickel-alloy coating by chemical reduction – without the use of an electric current. The chemical solution usually involves a Nickel-Phosphorus deposit containing between 7% to 14% phosphorus and a chemical reducing agent, such as sodium hypophosphite. This creates a Nickel-Phosphorus alloy coating – it is phosphorus which gives the component the corrosion resistance.

When a component is plated with Electroless Nickel, it has a durable, smooth, corrosion-resistant coating even when covering recesses, holes or parts of a complex geometry. This coating is highly sought-after in many industries, such as aerospace and automotive.”

Diffused Nickel Plating:

In the process of Diffused Nickel Plating, the component is first exposed to the chemical treatment which includes Electroless Nickel of  a high phosphorus content. After this the component is given a specific heat treatment – this process typically uses Heat Treatment at 610°C.  As a result, a diffusion layer is created between the Electroless Nickel deposit and the steel substrate which is typically between 3 to 5 µm.

Did you know, in Diffused Nickel Plating, heat treatment is applied at 610°C and the process takes 18 hours on average!
The average diffused layer thickness is between 3 to 5 µm.

The benefit of having heat treatment after the Electroless Nickel Plating process is that it is now possible to extend the operational life of subsea components by up to 30 years.

Diffused Nickel Plating is also popular within the marine industries due to its corrosion resistance compared with the high cost of manufacturing in stainless steel.

So, whether Electroless Nickel Plating or Diffused Nickel Plating is best for your project depends on a number of factors:

• What environments will the component be used in – is it abrasive, highly corrosive or subsea?
• How long is its lifespan expected to be?
• Would it be more affordable to manufacture in Diffused Nickel Plating rather than stainless steel – with the same properties?
• Is enhanced wear resistance important?

Our Electroless Nickel Plating and Diffused Nickel Plating experts can advise on which process is most suitable for your application. Call our team now on 01246 529014.