MIL-C-26074
Specifications

What is Mil-C-26074? 

When providing metal finishing for highly specified industries like Aerospace and Defense, there is no margin for error. At AOTCO, we comply with a wide range of military specs, including Mil-C-26074. 

Perhaps the most common Nickel-plating spec, Mil-C-26074 is the military standard for electroless nickel plating. The spec highlights four classes (1-4) and three grades (A, B, and C).

Class is used to identify what procedural changes or post treatments are required, and the three grades determine the minimum required thickness.  

Benefits of Electroless Nickel Plating Mil-C-26074 

Compared to Electrolytic Nickel, Electroless Nickel provides a unique set of qualities that are useful across a wide range of applications.  

• The finish is more ductile than its electrolytic counterpart, as well as more resistant to corrosion. 
• It also has great lubricity, making it more useful for components that need high wear resistance or flexibility.  
• Electroless Nickel Plating can bond with any metal substrate and has no thickness limits, making it more versatile than Electrolytic Nickel.  
• Electroless Nickel plating has higher hardness and abrasion resistance than Electrolytic Nickel, making it the stronger finish of the two.  

MIL-C-26074 Technical Notes

With this mil spec, there are a few key classifications an informed customer should understand

1. Grades– Thickness of Deposit
   1. Grade A (1000 microinches) – used for aluminum based alloys
   2. Grade B (500 microinches) – used for copper, nickel, cobalt, titanium, and beryllium
   3. Grade C (1500 microinches) – used for iron-based alloys
2. Class Number – Processing Guidelines
   1. Class 1 – As plated, no subsequent heat treatment. A bake for hydrogen embrittlement relief is not considered a heat treatment.
   2. Class 2 – heat treated to obtain required hardness: May be used on all metals not affected by heating to 500 degrees Fahrenheit and above.
   3. Class 3 – Aluminum alloys nonheat-treatable, and beryllium alloys processed to improved adhesion of the nickel deposit.
   4. Class 4 – Aluminum alloys, heat-treatable, processed to improve adhesion of the nickel deposit.

Mil-C-26074 Acceptable Base Metals

Iron, copper, aluminum, nickel, cobalt, beryllium, titanium, and their respective alloys.

Strikes and Underplating

Silver or copper plus silver may not be used as an underplate. When gold is applied to a copper rich surface such as brass, copper, bronze, or beryllium copper, an anti-diffusion underplate such as nickel shall be applied.