Our Plating Capabilities
Electroless nickel plating, or ENP, is an auto-catalytic (self-sustaining) chemical process used to deposit a coating of nickel on a solid surface for increased wear, lubricity, and corrosion protection without the use of electrical current. The plating process relies on the presence of a reducing agent which reacts with the metal ions to deposit metal. Metal plating has a variety of applications in aerospace, medical, military & defense and the transportation industry.
- Wide range of plating thicknesses from 0.00001 to 0.0020 inches
- Precision thickness
- Uniform plating – no dogboning as is typical in electroplating
- Low, mid and high phosphorus content for different corrosion resistance, hardness and appearance characteristics
- Baking after plating can yield hardness as high as RC70
- ASTM B733
Let us know if you have questions about ENP. If this is unclear, feel free to ask us for further details. Metal plating has a variety of applications in aerospace, medical, military & defense and the transportation industry.
Frequently Asked Questions
Process & Benefits
The Process of Plating
The process of ENP involves depositing an even layer of nickel-phosphorus alloy onto the surface of a solid such as metal or plastic. The way that this process is carried out is through dipping said solid into a water solution that contains nickel salt and hypophosphite salt – it doesn’t involve any sort of electric current passing through the water solution or the solid the plating is being coated onto. This process is carried out entirely through chemicals.
No matter what surface the nickel plating is being coated onto, it will create an even layer of metal to match its shape. Unlike electroplating, a different process entirely, nickel plating assimilates to the surface’s geometric shape and keeps an even density throughout.
There are a few reasons as to why nickel plating is used. It can be done purely for decoration and aesthetics, and it can also prevent corrosion of the metal or the wear and tear that happens to metal over time. It can also be used to apply composite coatings.
Before nickel plating an object, we make sure that the surface of it is clean and free of any dirt or debris. Most mistakes occur in nickel plating after a surface has been inadequately prepared. We also give the object a chemical bath, rinsed with water after each round. This is essential for ENP – the last thing you want is something trapped under the coating, because that ruins the plating in the long run. After the cleaning and plating bath are finished, we work on surface activation – making the surface of the object hydrophilic. This ensures that the object is made with a metal with catalytic activity, and if it’s not, we put a thin layer of said metal onto the object via a different process. After the plating is finished, we coat the object with an anti-tarnish solution, rinse it, and dry it to make sure there are no lingering stains. In some cases, it might be necessary to bake the object under heat to ensure the metal’s strength.
Benefits of Nickel Plating
- It conforms to the shape of any object – this includes ridges, holes, and varying sizes
- It creates an even coating in thickness and in volume
- It doesn’t call for electrical power
If done right, the plating process creates a coating that is less porous than most (this means it has a higher chance of being resistant to corrosion)
It can produce coatings that do not include mechanical stress.
You have options when it comes to the finish of your nickel plating – you can choose from either matte, semi-bright, or bright, depending on how you want the surface of your object to look.
Along with looking pretty, it also increases the strength of the item that it has coated.
Examples of Where Plating Benefits Are Common
The following are only a sample of potential uses and are not all the potential industries:
Steps of the Electroless Nickel Plating Process
What is the Plating Process?
ENP is the process of developing a nickel-alloy product to a metal surface without the electric current needed during the electroplating process. ENP is a chemical bath with a reducing agent such as sodium hydrophosphate, to deposit a nickel/phosphorus layer onto the surface of a metal or plastic. Advanced Technical Finishing specializes in this process, and we work to provide each applicant with a suburb product. Check out the flow chart below from researchgate.net for a quick overview of the process.
Benefits of Electroless Nickel Plating
ENP is popular mostly because of its insane corrosion resistance to hydrogen sulphide, salt water, oxygen and carbon dioxide. ENPs that have high deposits of phosphorus, about 10-14% pho, have no grain or porous sites for corrosion to set up. However, the phosphorus content of a deposit can be altered to best fit your needs for desired thickness and hardness.
ENP is also superior to electrolytic deposits because of its uniformity. The thick coating fills holes, slots and tubing to create a uniform surface across the entire substrate. The wear resistance properties and hardness are still top tier even without the heat treatment process.
Applying heat treatment can increase the hardness of the deposit, but it opens up microcracks where corrosion can set up over time. This is because ENP is at its most corrosion resistant state at the initial amorphous phase. ENP has a hardness between 68 and 72 on the Rockwell C Scale. The ENP Process provides you with a uniform deposit, even on odd shapes, unlike electroplating.
This is a cost-effective solution for subjects with high corrosion and wear possibilities because the process uses less equipment and needs fewer coats than electroplating. ENP extends the service life by providing a barrier of protection for metal or steel surfaces, all while providing applicants with a lower cost compared to common corrosion resistance alloys such as carbon steel or weld corrosion. The plating can be applied with little or no compressive stress, making the application gentle on the surface.
ENP Substrates Adhesion
Effective cleaning regimens of the substrate can ultimately determine the strength of the adhesion. With proper surface cleaning and preparation, adhesion to carbon steel is between 200-420 Megapascal Pressure Units (MPa). Stainless steel surfaces usually need an adhesive strength of 160-200 MPa.
What affects plating quality?
Poorly machined surfaces, burrs and cold shuts cannot be effectively plated because of their rough, uneven surface. Surfaces must be cleaned from any dirt, oil or alkaline cleaning products to achieve a high-quality ENP substrate. Controlling the plating baths also affects the ENP quality. Temperature, nickel ion concentration, hypophosphite concentration and pH need to be carefully supervised to ensure a uniform, high-quality plating finish. If the plating bath reaches below 80% nickel, then the bath will crash and no longer be usable. The chemical bath temperature should be 195°F.
Fabrication and Finishing Factors Requirements
There are certain fabrication and finishing factors to consider before plating. Weld roots and any corroded areas should be ground down, weld spatter should be removed and sharp edges radiused. All of these factors can help to provide you with a superb plating finish.
Substrates that are applicable for ENP include iron, nickel, brass, steel, copper, aluminum, plastic and stainless steel.
The Plating Process Steps
- We begin with a pretreatment of the surface. This includes a meticulous cleaning with a variety of agents to remove all oils, grease, grime and dirt.
- Next, we prepare the surface for plating by activating a proprietary solution or acid etch.
- Then, we apply electroless nickel by heating the chemical bath to 195°F and submerging the part to be plated. This step can take between 15-60 minutes, depending on desired level of thickness.
- After the plating is complete, the ENP process renders the deposit more resistant to corrosion, abrasion and friction.
- Lastly, ATF provides in-house testing of the finished product such as adhesion testing, salt spray testing and non-destructive testing.
Types & Benefits
Electroless Nickel Plating Types
There are many different types of electroless nickel used for plating. They contain different levels of phosphorus, low, medium or high, depending on the application needed.
MPEN is the most commonly used, containing medium levels of phosphorus, anywhere from 5-9%. Electroless nickel containing low levels of phosphorus, under 5%, provides uniform thickness on the inside of parts and configurations to reduce alkaline corrosion and grinding after plating. High phosphorus content, 10-13%, is most commonly used in coal mining, oil drilling and any other applications where there is heavy corrosion and wear possibilities.
Industries that can benefit from ENP
A few industries that can benefit from the ENP process include military, aviation, medical, oil and gas, construction, engineering, food processing and handling, textiles, chemicals and agricultural machinery. Any company that needs to protect their materials from corrosion, abrasion and wear, can benefit from ENP.
ENP provides flexibility when it comes to the volume and thickness of plating. This is beneficial because it allows for industrial parts such as valve pumps, field valves, engineering equipment, drive shafts, electrical and mechanical tools to be plated, making them more resistant.
Why Choose Us?
Advanced Technical Finishing has the fastest turnaround time in the industry. Our high quality standards paired with our professional and knowledgeable team of experts, are sure to deliver you a product you’ll be overly satisfied with.
ATF handles custom quotes, expedites and difficult masking jobs. We have an extensive list of plating, coating and finishing services available for our clients.
If you have a problem, we have a solution!