MIL-C-26074 E Electroless Nickel PlatingENS Technology provides complete electroless nickel plating services. We provide coatings to meet a variety of electroless nickel plating specifications:
- MIL-C-26074 E
- ASTM B733
- AMS C 26074
- AMS 2404
- AMS 2405
- and other industry or company standards
Contact ENS today for full-service electroless nickel plating.
Electroless Nickel Coatings
The electroless nickel plating process is used to provide uniform coatings on complex shapes, to improve wear and/or corrosion resistance, and/or to improve solderability on or for selected materials. Electroless nickel coatings are suitable for temperatures up to 1,000°F, although wear and corrosion resistance may degrade as temperatures increase.
Electroless nickel plating can be applied to a number of different base materials, including:
- Stainless steel
- Copper tungsten
- and other exotic metals
Classes & Grades of Electroless Nickel Plating
There are four (4) different classes and three (3) different grades of electroless nickel plating used throughout the industry to meet different specifications. The class of an electroless nickel plating refers to the post-plating heat treatment process that is used; the grade of an electroless nickel plating refers to its thickness.
Class (Heat Treating)
Heat treatment after electroless nickel plating provides evidence of proper adhesion and improves the crystalline structure of the amorphous deposit for greater hardness. Six heat-treat classes are available. Class 1 is for electroless nickel coatings that require no heat treatment. Class 6 requires heat treatment of 300-320°C for at least one hour to improve coating adhesion. Classes 2 through 5 exist at various levels between these two extremes.
Electroless nickel coatings are graded A, B, or C. Grade A requires a minimum thickness of 0.001”; Grade B requires a minimum thickness of 0.0005”; Grade C requires a minimum thickness of 0.0015”.
ASTM B733 Service Condition & Type
Within the ASTM B733 electroless nickel plating specification, there is an additional category known as service condition. Service condition is based on the thickness, starting with SC0 for minimum service requirements and continuing up to SC4 for severe service requirements.
ASTM B733 also specifies five (5) types of electroless nickel plating. Type refers to the coatings phosphorous content by weight.
- Type I electroless nickel coatings have no set requirement for phosphorous content
- Type II requires 1-3% phosphorous content, which provides very good corrosion resistance
- Types III and IV are “mid-phosphorous” formulas, which provide excellent utility for a wide range of applications
- Type V electroless nickel coatings require 10% or more phosphorous content, which provides excellent corrosion resistance; Type V coatings can withstand direct exposure to nitric acid for up to 30 seconds with no corrosion
Chemical Requirements for Electroless Nickel Plating
The chemical requirements for electroless nickel plating are very demanding and must be monitored closely. The chemical solution used for these coatings must be monitored for pH, temperature, nickel concentration, and hypophosphate concentration, among other factors. This solution must be replenished as required to maintain nickel and hypophosphate concentration between 90 and 100% of maximum.
At ENS Technology, we test our electroless nickel plating solution at least once per hour to maintain optimum nickel and hypophosphate concentration. Additionally, we mechanically agitate our plating solution to improve coating smoothness and prevent pitting, streaking, and other defects that can be caused by hydrogen bubbles on the surface of the workpiece.
Material & Hardness Requirements
When applying electroless nickel plating to steel workpieces, clients must provide information on the hardness of the base material prior to treatment. For all material substrates with a hardness of Rockwell C40 or higher, stress-relief heat treatment is required to minimize hydrogen embrittlement of the base material.
The Right Solution for Your Electroless Nickel Plating Specification
ENS Technology provides full-service electroless nickel plating for parts and components of all shapes and sizes. We require the following information from our clients prior to starting any electroless nickel plating project:
- Full description of the base material
- The number/revision of the applicable electroless nickel plating specification
- The required class/grade of the coating (plus service condition and type, if applicable)
- Various other information that deals with workmanship, inspection, and conformity of compliance to the specification
Quality Conformance Testing
Because each electroless nickel plating specification has slightly different requirements for post-treatment quality control, we use a variety of quality testing methods, from naked eye testing to micrometer measurements to x-ray fluorescence processes. We have two advanced x-ray fluorescence systems in-house, which enables us to test platings during and after processing and allows us to provide immediate validation of coating thickness post-treatment.
Test coupons provided for quality testing must be of the same material and stock as the workpiece(s) to ensure that the specification is met.
We provide adhesion testing to ensure that your electroless nickel plating meets your required specifications. Test coupons are bent to 180° over a mandrel with four times the thickness of the specimen. Adhesion test results are recorded by ENS Technology and kept on file at our facility for seven (7) years.