Electroless nickel
Electroless coating (also known as autocatalytic coating) is the deposition of a metallic coating by a controlled chemical reduction that is catalyzed by the metal or alloy being deposited. The electroless process has several advantages:
- Virtually unlimited throwing power
- Little or no excess deposit at high points
- Deposits of excellent physical and chemical properties
- Reduced hydrogen charging (hydrogen embrittlement)
- Ability to coat surfaces that would be difficult or impossible by electroplating
By far the most common form of electroless coating is nickel plating, which is actually a nickel-phosphorus alloy (2–10 % P). Electroless nickel is amorphous rather than crystalline in structure. These coatings have high hardness, natural lubricity, and good wear and abrasion resistance.
It is an economical treatment to improve the performance of carbon steel in mildly corrosive environments and where light wear may occur in service.
Electroless nickel can be deposited on the internal diameter of tubular components and other difficult-to-access surfaces.
The most common defect associated with electroless nickel is inadequate surface preparation. Proper adhesion depends on removing contaminants from the surface and on generating a fully active surface to start the process in all areas.
Frequently asked questions
What is electroless nickel?
A coating of nickel with a percentage of phosphorus.
How does electroless nickel work?
It does not require anodes or an outside power source. Chemical reactions on the surface of the part cause the deposition of the nickel alloy on all wetted surfaces, which in turn produces a uniform thickness.
What are the benefits of electroless nickel?
- Corrosion protection
- Excellent adhesion
- Hardness
- Wearability
- Uniform deposit regardless of the geometry of the part
What are the advantages of electroless nickel versus electrolytic nickel?
- Uniformity of thickness
- Better corrosion protection
- Superior adhesion
- Better lubricity
What is the appearance of electroless nickel plating?
An electroless nickel finish is similar to stainless steel in coloration. The surface finish replicates that of the base metal: a brightly polished surface will have a bright finish after plating, and a matte or satin surface will have a matte or satin finish after plating.
Can it be applied on aluminum?
Yes, with proper pretreatment it is possible.
What thickness is applied?
The thickness typically ranges between 0.0005” and 0.002”. Due to the uniformity and thickness control, parts do not require subsequent grinding.