// FINISHING — ELECTROLESS NICKEL
Electroless Nickel Plating
Autocatalytic nickel-phosphorus deposit on aluminum, steel, copper, and other metals — perfectly uniform thickness on complex geometry, improved hardness, and corrosion resistance.
Electroless nickel plating uses a chemical reduction reaction rather than electrical current to deposit a nickel-phosphorus alloy uniformly onto a part surface. Because the deposition is not driven by a current field, it follows the geometry exactly — recesses, bores, blind pockets, and external surfaces all receive the same thickness. This makes electroless nickel the go-to choice for complex precision parts where dimensional uniformity matters as much as the surface properties.
Why electroless nickel over electrolytic plating
Conventional electroplating distributes metal in proportion to current density, which means edges and high spots get more deposit and recesses get less. On a simple flat or cylindrical part the difference is manageable. On a complex machined part with pockets, undercuts, and fine threads, current-distribution problems produce dimensional variation that defeats the purpose of plating. Electroless nickel deposits uniformly regardless of shape — a critical advantage for precision components.
- Uniform deposit thickness on all surfaces — pockets, bores, and threads included
- No current distribution problems that thin recesses or build up edges
- Increased hardness over base material (as-plated and heat-treatable)
- Good corrosion resistance across a range of environments
- Multi-substrate capability: aluminum, steel, copper alloys, and more
Hardness and corrosion properties
The nickel-phosphorus deposit is harder than many base materials and can be further hardened by a post-plate heat treatment. As-plated hardness is typically in the 45–55 HRC range depending on phosphorus content; post-bake heat treatment can drive it above 60 HRC. Corrosion resistance is excellent, particularly in neutral and mildly acidic environments, and medium-to-high phosphorus deposits are essentially non-magnetic — relevant for some electronics and sensor applications.
Substrate and size capability
Electroless nickel can be applied to aluminum, steel, copper, brass, and most other engineering metals. Our finishing partner NorTex handles parts up to 40" × 24". Phosphorus content (low, medium, high) can be specified to tune hardness and magnetic properties for your application.
| Process | Autocatalytic (electroless) nickel-phosphorus deposition |
|---|---|
| Key advantage | Uniform thickness on any geometry — no current-field variation |
| Substrates | Aluminum · Steel · Copper · Brass · Other metals |
| Max part size | 40" × 24" |
| As-plated hardness | ~45–55 HRC (heat-treatable to 60+ HRC) |
| Corrosion resistance | Good — excellent in neutral/mildly acidic environments |
Electroless nickel is a common finishing step for complex 5-axis machined components where uniform coating on internal geometry is required. It pairs well with our aluminum machining and stainless steel machining work.
// FAQ
Frequently asked questions
Electroless nickel deposits uniformly on all surfaces regardless of geometry because it uses a chemical reaction rather than electrical current. Electrolytic plating concentrates deposit where current density is highest — edges and high spots — and thins in recesses. For complex machined parts with pockets and bores, electroless nickel is the only way to guarantee consistent thickness everywhere.
Yes. As-plated, the nickel-phosphorus deposit is typically 45–55 HRC depending on phosphorus content. A post-plate bake (heat treatment) can increase hardness above 60 HRC, making electroless nickel competitive with hard chrome for wear applications.
Aluminum, steel, copper, brass, bronze, and most engineering alloys. The plating process requires surface activation appropriate to the base metal — we review your material at the quoting stage.
Thickness is controlled and specified — typically 0.0002" to 0.001" per side depending on the application. Because the deposit is uniform, pre-plating dimensions can be planned precisely for features that must hit a final size after plating.
Send us the hard one.
Upload your drawing or STEP file and we'll come back with pricing and lead time — from a single high-mix part to full production runs, held to exacting tolerances.