An introduction to electroless nickel plating (ENP)
Covering metals in a coating is a common practice to protect machine elements, pipes and so forth from corrosion and to improve the look of the item. Silver-plated jewellery and household items are an example of this. Many plating technologies use electricity to help create the chemical reaction.
ENP, or electroless nickel plating, is different as it uses a chemical reaction to plate the material underneath, which could be metal but could also be a non-conductive material such as plastic.
Types of ENP
There are several types of ENP that are offered by specialists. These are:
. Low phosphorus – good for high-temperature applications
. Medium phosphorous – provides good corrosion and wear protection
. High phosphorous – a non-magnetic coating that gives the best corrosion protection
Specialists such as Poeton: www.poeton.co.uk/standard-treatments/electroless-nickel-plating/ also offer a grade between medium and high which combines the benefits of high phosphorus with excellent corrosion protection. The hardness of the ENP coating can be improved by heating after application.
Benefits of ENP
ENP provides cost-saving benefits for equipment and machinery as the coating helps to prevent corrosion and wear. Because it is a chemical process, the coating can be applied evenly across the piece both inside and out, and in hard-to-reach areas.
Providing protection against salt water, carbon dioxide, oxygen, and hydrogen sulfide, ENP is useful for a wide variety of applications and equipment. The high phosphorous coating is also amorphous, providing no phase or grain boundaries where corrosion can take hold.
Ensuring Good Quality Plating
You should talk to your surface finishing company about how they will prepare the surface to ensure that they get the best quality finish possible. This could include:
. Cleaning – making sure that the surface is clean of oil, dirt, and any soap that contains alkaline cleaners
. Preparation – the surfaces need to be smooth and clear of defects such as burrs or cold shuts to be plated effectively. Grit blasting prior to plating is often offered as a service.
. Plating baths – your plating partner should have good knowledge of controlling the temperature, pH, and concentration to ensure the best quality coating.
ENP is a valuable means of increasing the life of parts and machinery, however, you need to select your plating partner carefully to ensure that you get the best out of the process.