Surface Finishing

Electroless Nickel Plating Services

Protect complex parts with a uniform nickel-phosphorus coating that improves wear and corrosion resistance while keeping coating buildup controlled.

Machining + Plating Coordination

Critical Dimensions Reviewed Before Plating

Our team reviews coating buildup against the machined dimensions so critical finished features can be planned before plating.

Request a Plating Quote

Share the part and coating requirements for engineering review.

ISO 9001 Quality Management · Files are handled confidentially.

Typical Coating Thickness

3 to 40 µm*

Typical Pre-plating Surface

Ra 1.6 µm

Common Visual Appearance

Semi-Bright

Quality Management

ISO 9001: 2015

*Reference range only. Final thickness depends on the substrate, geometry, specification, dimensional allowance, and performance requirements.

Engineering-Focused Plating

Why Choose Us

Practical support from coating selection and drawing review through processing, inspection, and delivery.

Uniform Coating Thickness

Chemical deposition provides consistent coverage across many edges, recesses, holes, threads, and complex surfaces.

Application-Based Selection

Coating requirements are reviewed against substrate, corrosion exposure, wear, hardness, and dimensional needs.

Controlled Preparation

Cleaning, activation, and substrate-specific pretreatment support coating adhesion and repeatable results.

Selective Masking

Threads, sealing faces, contact areas, and other features can be protected according to drawing requirements.

Inspection Support

Thickness, dimensions, appearance, adhesion, and application-specific documentation can be reviewed with the project.

ISO 9001 Quality System

Processing and inspection are managed through an ISO 9001 quality management system.

About the Process

What Is Electroless Nickel Plating?

Electroless nickel plating is an autocatalytic chemical process that deposits a nickel-phosphorus alloy onto a properly prepared substrate. Because deposition is driven by a controlled chemical reaction rather than external electrical current, wetted surfaces receive comparatively uniform coverage.

This makes the process useful for precision parts with bores, recesses, threads, internal passages, complex edges, and other features that are difficult to cover consistently using line-of-sight methods.

Process Scope

Electroless Nickel Plating Capabilities

Final processing requirements are established from the drawing, substrate, coating area, performance targets, and applicable specification.

Capability	Engineering Information
Coating System	Functional nickel-phosphorus alloy deposited by an autocatalytic chemical process.
Phosphorus Level	Selected according to corrosion, wear, hardness, magnetic behavior, and specification requirements.
Coating Thickness	Reference range: 3 to 40 µm. Final thickness is confirmed from the application, substrate, dimensional allowance, and specification.
Surface Preparation	Typical starting condition: smooth machined, approximately Ra 1.6 µm (Ra 63 µin), unless the drawing requires otherwise.
Visual Appearance	Smooth, semi-bright metallic appearance. Electroless nickel is primarily a functional rather than cosmetic finish.
Base Materials	Common engineering alloys can be reviewed; pretreatment depends on the exact material and condition.
Masking	Selective masking for threads, sealing surfaces, fits, contact areas, holes, and other identified features.
Post-Treatment	Heat treatment, baking, polishing, grinding, honing, or other finishing options reviewed when applicable.
Production Volume	Prototype, low-volume, and production requirements reviewed according to part size and process scope.
Inspection	Coating thickness, dimensional, visual, adhesion, and corrosion requirements reviewed with the quotation.

*Coating thickness, dimensional allowance, appearance, and performance depend on the substrate, component geometry, surface condition, phosphorus level, post-treatment, and application requirements.

Functional Performance

Benefits of Electroless Nickel Plating

Uniform Thickness

Comparatively consistent deposition supports complex shapes and controlled coating allowance.

Corrosion Resistance

Suitable coating selection can help protect parts exposed to moisture, salts, and industrial chemicals.

Wear Resistance

A harder functional surface can reduce wear on sliding, contacting, and repeatedly handled components.

Surface Hardness

Composition and available post-treatment can be selected to improve hardness for demanding service.

Dimensional Control

Uniform deposition helps engineers plan coating allowance on critical interfaces and fits.

Reduced Friction

The coating can improve surface behavior in molds, tooling, and selected moving interfaces.

Internal Coverage

Many bores, recesses, and wetted passages can receive coating without direct line of sight.

Material Upgrade

A functional surface can be added while retaining the bulk properties of the selected base material.

Coating Selection

Selecting the Right Phosphorus Level

The coating should be selected based on the operating environment and required properties, not appearance alone.

Coating Type	General Characteristics	Typical Selection Drivers
Low Phosphorus	Often selected where higher as-plated hardness, wear behavior, or specific magnetic and electrical characteristics matter.	Wear surfaces, tooling, and selected alkaline environments.
Medium Phosphorus	Provides a balanced combination of hardness, corrosion performance, appearance, and process economy.	General engineering components and dimensional restoration applications.
High Phosphorus	Commonly selected for stronger corrosion performance and typically non-magnetic behavior in the as-plated condition.	Chemical exposure, oil and gas, electronics, and corrosive environments.

*Available phosphorus levels and property ranges must be confirmed during engineering review for the specific project.

Substrate Review

Compatible Base Materials

Pretreatment must be matched to the exact alloy, temper, heat treatment, weld condition, and existing surface condition.

Aluminum Alloys

Material-specific cleaning, deoxidizing, and activation are required.

Carbon Steel

Surface cleanliness and heat-treatment condition are reviewed.

Alloy Steel

Hardness and hydrogen-embrittlement requirements may apply.

Stainless Steel

The passive surface requires controlled activation.

Copper Alloys

Alloy composition and surface condition affect pretreatment.

Brass

Composition and zinc content should be identified.

Tool Steel

Hardness, grinding allowance, and post-treatment require review.

Nickel Alloys

Exact grade and service requirements should be provided.

Controlled Workflow

How Electroless Nickel Plating Works

Each stage is matched to the substrate and drawing requirements.

Part Review

Drawing, coating areas, substrate, tolerances, and masking are confirmed.

Cleaning

Oil, grease, residue, and manufacturing contaminants are removed.

Activation

Material-specific pretreatment creates a clean, active surface.

Masking

Features that must remain uncoated are protected.

Deposition

The part remains in the controlled bath until the target coating is reached.

Inspection

Parts are rinsed, post-treated as specified, and checked.

Before You Send the Drawing

Design Considerations for Plated Parts

Clear coating callouts reduce ambiguity and help protect final dimensions.

Coating Allowance

Account for coating on bores, diameters, grooves, threads, fits, and mating surfaces. Identify the final dimension and whether it applies before or after plating.

Masking Boundaries

Mark every uncoated area and define clear start and stop locations for sealing faces, contacts, threads, holes, and interfaces.

Blind Holes and Passages

Identify internal features requiring coating and geometries where drainage, trapped solution, or air pockets may affect processing.

Threaded Features

State whether internal and external threads should be plated, masked, chased, or manufactured with coating allowance.

Surface Condition

The coating follows the underlying surface. Tool marks, scratches, porosity, welds, and defects can remain visible after plating.

Post-Plating Finishing

Identify grinding, honing, polishing, heat treatment, baking, or final machining so sufficient allowance can be planned.

Process Comparison

Electroless Nickel vs. Electrolytic Nickel

Neither process is universally better; selection depends on function, geometry, appearance, specification, and cost.

Factor	Electroless Nickel	Electrolytic Nickel
Deposition Method	Autocatalytic chemical reaction	Applied electrical current
Thickness Distribution	Comparatively uniform on wetted surfaces	Varies with current density and geometry
Complex Geometry	Good coverage of many recesses, bores, and internal features	Greater risk of edge buildup and low-current areas
Composition	Commonly nickel-phosphorus alloy	Primarily nickel
Dimensional Planning	More predictable where deposition remains uniform	Uneven buildup may require additional allowance
Common Purpose	Functional corrosion, wear, hardness, and dimensional performance	Functional or decorative, depending on the process

*Available phosphorus levels and property ranges must be confirmed during engineering review for the specific project.

Where It Is Used

Industries

Application requirements vary by environment and component function.

Aerospace & Defense

Automotive

Oil & Gas

Marine

Electronics

Industrial Machinery

Tooling & Molding

Energy & Automation

Common Part Types

Components

Complex coverage and functional performance make the process useful across many precision parts.

Finished Components

Gallery of Plated Parts

Examples of precision components with functional electroless nickel-plated surfaces.

Verification

Quality Control and Inspection

Inspection scope should be agreed before production and tied to the drawing or applicable specification.

Coating-Thickness Measurement

Measurement method and locations are selected according to part geometry and reporting requirements.

Visual Inspection

Appearance, coverage, staining, pitting, roughness, and visible defects can be checked.

Dimensional Inspection

Critical dimensions can be identified for pre- or post-plating inspection.

Application-Specific Testing

Adhesion, corrosion, hardness, and additional requirements are reviewed with the project.

Specifications and Documentation

Prolean MFG can review customer drawings and commonly referenced plating requirements. Support for a specific standard must be confirmed before production.

Available project documents may include coating-thickness results, dimensional reports, certificates of conformity, and other agreed inspection records.

Start With an Engineering Review

Define the Plating Requirements Before Production

Send the drawing, base material, coating area, thickness, masking, quantity, service conditions, and applicable specification. Our team will review the practical processing requirements.

For a Faster Review

Engineering Answers

FAQs

What is electroless nickel plating?

It is an autocatalytic chemical process that deposits a nickel alloy onto a properly prepared surface without applying external electrical current.

How is electroless nickel different from electroplated nickel?

Electroless deposition is chemically driven and provides comparatively uniform thickness on wetted surfaces. Electrolytic nickel uses electrical current, so deposition varies with current density and geometry.

Can aluminum be electroless nickel plated?

Many aluminum alloys can be plated after suitable cleaning, deoxidizing, and activation. The exact alloy, temper, geometry, and service requirement must be reviewed.

Can holes and internal surfaces be coated?

Many wetted bores, recesses, threads, and internal passages can receive comparatively uniform deposition, provided solution access, drainage, and geometry are suitable.

Does electroless nickel change part dimensions?

Yes. Coating adds material to every plated surface, so thickness allowance must be considered on bores, diameters, grooves, fits, sealing surfaces, and threads.

Which phosphorus level should I specify?

Selection depends on corrosion exposure, wear, hardness, magnetic behavior, post-treatment, and the applicable specification. Engineering review is recommended.

Should threaded features be masked?

That depends on the thread class, coating thickness, assembly requirements, and whether coating is functionally required. The drawing should clearly identify plated and masked threads.

Can the coating be heat treated?

Post-plating heat treatment may be used for selected property requirements, but substrate effects, distortion, corrosion behavior, and applicable specifications must be reviewed.

Which standards can be supported?

Provide the required standard and revision with the quotation request. Support must be confirmed for the specific substrate, coating type, thickness, testing, and documentation scope.

What information is required for a quote?

Send the drawing, base material, heat-treatment condition, coating areas, masking, thickness, quantity, final tolerances, service conditions, and applicable specification.