Endura CoatingsElectroless Nickel Plating Coatings
Series 200 Electroless Nickel Plating
For Ferrous & Non-Ferrous Metals
Endura Series 200 Electroless Nickel Plating is an autocatalytic nickel-phosphorus coating process that deposits a uniform, wear-resistant surface on ferrous and non-ferrous substrates — without the use of electrical current. Because the process relies on a controlled chemical reduction reaction rather than an applied charge, the coating conforms precisely to complex geometries, deep recesses, threads, and internal cavities, making it one of the most dimensionally consistent surface finishing options available.
Certified to ASTM B733 and MIL-C-26074 electroless nickel plating specifications, Series 200 coatings deliver a measurable improvement in hardness, wear resistance, and corrosion protection. Depending on application requirements, coating chemistry can be modified to enhance specific performance properties — including dry film lubrication, release characteristics, and chemical resistance. Select formulations can withstand operating temperatures in excess of 1,000°F, making them viable for high-heat industrial and aerospace environments.
We offer a vast array of RoHS compliant Electroless Nickel Plating systems of which include, but are not limited to:
- Composite Diamond Coatings
- Electroless Nickel with Boron Nitride
- Electroless Nickel Teflon (EN & PTFE)
- High Phosphorous Electroless Nickel (x>10%)
- Medium Phosphorous Electroless Nickel (6-9%)
Endura Series 200 Electroless Nickel Plating is certified to the most widely recognized electroless nickel plating specifications in the aerospace, defense, and industrial sectors. Our team has the process controls and quality documentation in place to certify parts to customer-specified requirements across a broad range of classes, grades, types, and service conditions. The two primary Electroless Nickel Plating specifications we certify are MIL-C-26074 and ASTM B733:
MIL-C-26074
Classes:
| Class | Heat Treatment | Substrate Application |
|---|---|---|
| Class1 | No heat treatment (except embrittlement bake for hardened steel >Rc 40) | Steel, copper, brass |
| Class2 | Baked to minimum 800 Knoop hardness | General hardened applications |
| Class 3 | 375°F bake for adhesion | Steel and most metals |
| Class 4 | Low-temp bake (275°F) | Aluminum and heat-sensitive alloys |
Grades:
| Grade | Min. Thickness |
|---|---|
| Grade A | 0.001" (25 µm) |
| Grade B | 0.0005" (13 µm) |
| Grade C | 0.0015" (38 µm) |
ASTM B733
Types:
| Type | Phosphorus % | Notes |
|---|---|---|
| Type I | No Requirement | General purpose |
| Type II | 1-3% | Very good corrosion resistance |
| Type III | 2-4% | Excellent utility, mid-range |
| Type IV | 5-9% | Medium phosphorus, wear applications |
| Type V | >10% | High phosphorus, maximum corrosion resistance |
Classes:
| Class | Heat Treatment |
|---|---|
| Class1 | No heat treatment required |
| Class2 | Baked to minimum 850 HK hardness (up to 400°C) |
| Class 3 | Heat treated at 180-200°C for adhesion |
| Class 4 | Heat treated at 120-130°C (low-temp substrates) |
| Class 5 | Heat treated at 140-150°C |
SC (Service Condition)
| SC | Service Level | Min. Thickness |
|---|---|---|
| SC 1 | Mild | 5 µm |
| SC 2 | Moderate | 13 µm |
| SC 3 | Severe | 25 µm |
Specific nickel plating-based coatings are RoHS and FDA compliant, USDA approved and biocompatible (ISO 10993).
For applications where standard electroless nickel plating specifications aren't enough, Endura® offers Infused Matrix™ coatings — a proprietary next-generation nickel coating system that goes beyond the performance envelope of conventional ASTM B733 and MIL-C-26074 certified coatings.
Infused Matrix™ coatings are produced through a patented vacuum impregnation process that drives sub-micron fluoropolymer particles deep into the hardened nickel matrix — not simply applied to the surface. The result is a coating that delivers:
- Superior corrosion resistance — exceeding standard electroless nickel-phosphorus performance
- Low friction & non-stick release — comparable to traditional PTFE/Teflon coatings, but within a wear-hardened substrate
- Greater surface hardness — harder and more durable than conventional nickel-based coatings
- Thermal stability — maintains performance integrity at elevated temperatures
Unlike topically applied Teflon or PTFE coatings that can wear away, Infused Matrix™ integrates the fluoropolymer into the nickel matrix itself — meaning the release and lubricity properties are sustained throughout the life of the coating, not just on the surface.
Series 200 - Electroless Nickel Plating Process
For Ferrous & Non-Ferrous Metals
Process Illustration
The Endura Series 200 electroless nickel plating process is engineered to consistently meet the deposit requirements of ASTM B733 and MIL-C-26074 electroless nickel plating specifications. Each step in our process is controlled and documented to support certification requirements across all applicable types, classes, grades, and service conditions.
Step 1: Proprietary Surface Preparation
Parts undergo a multi-stage cleaning process to remove oils, oxides, and surface contaminants before entering the plating bath. Thorough surface preparation is critical to achieving the adhesion bond strength required by MIL-C-26074 and ASTM B733 specifications.
Step 2: Nickel Matrix Deposit
Parts are immersed in our controlled electroless nickel bath, where an autocatalytic chemical reduction reaction deposits a uniform nickel-phosphorus matrix directly onto the base metal — across all surfaces, recesses, threads, and internal geometries — without the use of electrical current.
Step 3: Fluoropolymer Deposit
The newly formed nickel matrix is vacuum infused with sub-micron sized fluoropolymer particles to optimize specific coating performance objectives — including lubricity, release characteristics, and enhanced corrosion resistance.
Step 4: Fluoropolymer Deposit — Hardening & Bonding
The infused coating is thermally processed to develop final hardness and achieve a fully bonded surface. The newly formed, hardened, and bonded coating will not chip, crack, flake, or peel from the base metal under normal service conditions.
Step 5: Fluoropolymer Infusion — Coating Growth
The completed Infused Matrix™ coating achieves full dimensional growth across the base metal substrate, producing a uniform, performance-optimized surface ready for inspection, thickness verification, and certification documentation.
Frequently Asked Questions
What is ASTM B733 electroless nickel plating?
ASTM B733 is the standard specification for autocatalytic nickel-phosphorus coatings on metal substrates. It provides a complete framework for specifying a coating across four key variables: Type (phosphorus content), Class (heat treatment), Service Condition (minimum thickness), and substrate material.
A complete callout reads: "Electroless Nickel per ASTM B733, Type V, SC 3, Class 2." Endura® Series 200 is certified to ASTM B733 across all commercially available types, classes, and service conditions.
Endura® Series 200 electroless nickel plating is certified to ASTM B733 across all commercially available types, classes, and service conditions.
What is the difference between MIL-C-26074 and ASTM B733?
Both are widely used electroless nickel specifications, but they differ in origin and structure. MIL-C-26074 is a U.S. military specification that classifies coatings by Class (heat treatment) and Grade (thickness) — most commonly referenced on defense and aerospace drawings. Its successor, AMS-C-26074, is now the preferred aerospace callout.
ASTM B733 is a civilian industry standard with a more granular system — Type, Class, and Service Condition — giving engineers greater precision in specifying performance requirements.
Endura® is certified to both and can support documentation for either or both on a single order.
What phosphorus content is used in high phosphorus electroless nickel?
High phosphorus electroless nickel contains greater than 10% phosphorus by weight — corresponding to Type V under ASTM B733. Higher phosphorus content delivers superior corrosion resistance, a non-magnetic amorphous microstructure, and hardness exceeding 65 Rc after heat treatment.
Endura® Series 200 high phosphorus EN is available as a standalone coating or as the base matrix for our Infused Matrix™ fluoropolymer-enhanced systems.
What industries require MIL-C-26074 or ASTM B733 certified coatings?
Industries specifying these standards include:
- Aerospace & Defense — airframe, engine, actuation, and landing gear components
- Military & Government — defense hardware and government-contracted components
- Oil & Gas — downhole tools, valve bodies, and pump components in corrosive environments
- Medical & Pharmaceutical — surgical instruments and processing equipment
- Automotive & Heavy Equipment — hydraulic and fuel system components
- Electronics & Semiconductor — connectors and contacts requiring non-magnetic properties
If your drawing calls out MIL-C-26074, AMS-C-26074, or ASTM B733, Endura® can support your full documentation and certification requirements.
What is the difference between electroless nickel and electroplated nickel?
Electroplated nickel uses electrical current to deposit a coating — which means thickness varies across the part surface depending on geometry. Electroless nickel uses no electricity, relying instead on an autocatalytic chemical reaction that deposits a uniform nickel-phosphorus alloy across all surfaces, including recesses, threads, and internal cavities.
For complex geometries, tight tolerances, and demanding service environments, electroless nickel is almost always the superior choice. Electroplated nickel may be suitable for simpler parts where decorative finish is the primary requirement.
Please complete our Coating Requirement Questionnaire
or call us
at 1.800.336.3872 to review & discuss your project requirements.
