Cadmium is robust and versatile. Cadmium has a silvery white metallic appearance with excellent corrosion resistance, which functions as a "sacrificial coating," corroding before the substrate material. To enhance the corrosion protection of cadmium plating, chromate conversion coatings can be applied over the plated metal. Finishes available are:
- Bright - Giving the surface a silvery / white appearance.
- Dull - Giving the Cadmium’s natural state, being a matt deposit.
- Chromate - Applying a golden yellow film with a high degree of protection against atmospheric corrosion.
- Olive drab - Producing a dark green finish, with a further increase in corrosion resistance.
Cadmium plating offers an exceptional bonding surface for adhesives, such as those used in aircraft manufacture, and is the preferred coating for salt-water environments. The coating is electropositive to iron and has a very low contact potential minimizes corrosion caused by dissimilar metals. Cadmium is a controlled substance and can only be used in specific applications.
In some applications, zinc-nickel alloy plating may be an acceptable alternative to cadmium plating.
Cadmium Plating Capabilities
- LHE process, a specialised aerospace process for high strength steels
- Rack and Barrel Plating Available
- Post-Treatment passivates
- Application of Zinc Phosphate as a Painting Pre-Treatment
- Precise masking for Selective Surface Plating
- Salt Spray Corrosion Test
- Plating thickness analysis using XRF technology, Magnetic methods
- Defence Standards (Def-Stan)
- British Standards (BS-EN)
- Aerospace Material Specification (AMS)
- WHPS 257
- Agusta Westland
Typical Cadmium Applications
- Aerospace: corrosion protection on flight-critical components
- Defence, used for electrical field connectors
- Oil and gas, used for bolts and fixtures
- Nuclear, used in submarine actuators
- While cadmium offers engineering properties that have yet to be matched by a single finish, it is highly toxic and subject to strict environmental controls. For this reason, EIC Finishing Services, incorporates the latest closed loop cadmium plating equipment at its facility, and are actively involved in the development of viable alternatives to cadmium plating.