A form of alloy treatment, electroless nickel plating involves depositing a metallic coating via a controlled chemical reduction and without the use of electrical current. Also known as autocatalytic coating, the practice is commonly used to strengthen resistance and hardness in metals or plastics. It is commonly used to boost corrosion resistance on applications such as fasteners, pipes and valves. In engineering, electroless nickel plating involves the use of a nickel-phosphorous deposit. The higher the quantity of phosphorus therein, the more the plating will be able to withstand corrosion.
Electroless nickel plating, also known as EN or ENP can be used on a wide range of materials, including hardened steel, brass, copper, stainless steel and aluminium. Recent forecasts expect demand for nickel-based plating to increase by 7% between now and 2033.
What are the benefits of electroless nickel plating?
Electroless nickel plating has many advantages over alternatives such as electroplating. It is used to boost hardness, resistance, corrosion and friction in all sorts of materials. Using nickel gives great corrosion resistance against common substances which are known to corrode surfaces, including salt water, oxygen, carbon dioxide and hydrogen sulphide. ENP also has the advantage of being able to create a uniform coating, even on the most complex of surfaces. This makes it ideal for use inside often awkwardly-shaped parts such as pipes or tubes.
Electroless nickel plating also results in low hydrogen absorption. This reduces the risk of hydrogen embrittlement in metals. Overall, ENP is a cost-effective way to enhance corrosion resistance in applications which would be affected, thus extending their service life. It offers a much simpler process than electroplating, as no electric current is needed.
How does electroless nickel plating work?
In ENP, a nickel-based deposit is used which also contains 2 to 14% phosphorus. The proportion of phosphorus needs to be adjusted to fit the application. Experts such as poeton.co.uk/standard-treatments/electroless-nickel-plating/ can recommend the best type of electroless nickel plating for your application. ENP is deposited using a chemical reducing agent which reduces nickel ions to metallic nickel.
Prior to electroless nickel plating, the surfaces need to be thoroughly prepared, with dirt, dust and oil removed. All contaminants and corrosion spots must be eliminated and the surface needs to be as smooth and even as possible. Plating baths also need to be well managed and maintained to ensure high-quality nickel plating.