MIL-C-14550B Copper Plating
ENS Technology provides full-service electrolytic copper plating. Our advanced copper plating capabilities enable us to meet a number of specifications, including:
- ASTM B734
- AMS 2418
- and other industrial and international standards
Contact ENS today for a complete copper plating service.
Electrolytic Copper Plating
We have the experience and technical expertise to provide a number of copper plating options, including electrolytic copper plating. This process results in a smooth, continuous, and uniform coating which adheres reliably to the substrate material and is not coarse or crystalline on its surface. Copper plating may have a matte to a very shiny finish. High purity copper is very soft and malleable; strength and be improved by alloying copper with other elements such as beryllium or chromium.
Mil-spec copper plating provides very high thermal and electrical conductivity. It can be used to improve brazing characteristics, as a high-temperature lubricant, or as a heat-treatment “stop off,” among other applications.
Copper plating is also often used as an underplanting to enhance the adhesion of silver, gold, or other plating materials, to improve their electrical properties and/or corrosion resistance, and to prevent the migration of alloying elements into the final plated deposit.
We can apply electrolytic copper plating to a wide range of substrates, including:
- Mild steels
- Stainless steels
- Hardened & tool steels
- Aluminum & aluminum alloys
- Nickel 200
- and other exotic metals
Stress Relief Treatment
All steel parts receiving military-grade copper plating must be given a stress relief treatment at a minimum of 375° ±25°F (191° ±14°C) for at least three hours prior to cleaning and plating if they contain, or may contain, residual tensile stresses. The temperature and duration of the stress relief treatment must be sufficient to achieve maximum stress relief without reduction in hardness to less than the specified minimum. ENS provides stress relief treatments, as needed, for MIL-C-14550B coatings.
Hydrogen Embrittlement Relief
For hydrogen embrittlement relief, all steel parts having a tensile strength greater than 210 KS1 receiving military-grade copper plating must be baked at 375° ±25°F (191° ±14°C) for 24 hours within four hours after plating. Plated springs and other parts that are subject to flexing should not be flexed prior to baking. ENS performs hydrogen embrittlement relief, as needed, for military-grade copper plating projects.
To meet copper plating mil-spec standards, the adhesion of the plating must be such that, when inspected under 4x magnification, it doesn’t show separation from the substrate. If possible, the test should be performed on a workpiece which can be bent to 180°; the test piece must be clamped in a vise and bent and re-bent until the substrate material fractures; if properly adhered, no significant portion of the electrolytic copper plating will be removable with a sharp instrument. ENS records all adhesion test results and keeps them on file at our facility for seven (7) years.
Classes of MIL-C-14450B Copper Plating
There are five (5) different classes of military-grade copper plating, each intended for different applications. The class refers to the thickness of the plating.
- Class 0: 0.001”-0.005” minimum; used as a heat treatment stop-off shield
- Class 1: 0.001” minimum; for carburizing shield, decarburizing shield, and PCB plated thru-holes, or as specified
- Class 2: 0.0005” minimum; undercoating for nickel and other metals
- Class 3: 0.0002” minimum; to prevent substrate metal migration that can affect solderability
- Class 4: 0.0001” minimum; same as Class 3 copper plating
Chemical Requirements for Electrolytic Copper Plating
Like all of our plating and coating processes, electrolytic copper plating has strict chemical requirements. To ensure quality and consistency in our copper plating service, the chemical solution used for these coatings must be closely monitored for temperature, pH, and chemical concentration, among other factors, and replenished as needed.
ENS tests our electrolytic copper plating solution at least once an hour to ensure that the optimum chemical concentration is maintained. We mechanically agitate our plating solution to improve overall coating smoothness and prevent pitting and other defects that can be caused by hydrogen bubbles on the surface of the treated part.