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Cadmium Plating
Current Usage 
Cadmium plating is used for two primary purposes:
  1.To provide sacrificial corrosion protection to steel components.
  2.To provide galvanic compatibility between electronegative materials such as Al and Mg, and more noble materials such as stainless steels.
Cd plate is normally chromated with a typical hexavalent chromium conversion coating.

Common Applications

Versions of Cd Plate

Specifications
Corrosion Protection
  • High strength steel landing gear
  • High strength steel actuators
  • Steel fasteners (bolts, rivets)
  • Electrical connector shells


    • Galvanic Compatibility
  • Stainless steel actuators, sensors
  • Rivets for AL aircraft skins

    • Bright Cd for low strength components

    • LHE (low hydrogen embrittlement) Cd and TiCd  for high strength steels

    • Brush Cd for touch-up and repair

    • MIL-STD-870B (inactive)

    • MIL-STD-1500 (LHE Cd, inactive)

    • AMS 2401 (LHE Cd, inactive)

    • QQ-P-416

    • MIL-C-8837B vacuum Cd

    • AMS-C-8837 vacuum Cd

    • AMS 14198·79 (TiCd)

    ESOH Issues
    Cd is a heavy metal cumulative poison and a probable (Class B1) carcinogen.  Cd plating chemistry involves the use of several toxins.  Cd is deposited from a cyanide bath and post-treated with chromate sealant.  Cd, chromate, and cyanides are all heavily regulated because of their toxicity.  Cd regulations:

    • EPA: Limit 5ppb in drinking water

    • OSHA:  Cd PEL is currently 0.1mgm-3 for fumes, 0.2mgm-3 for dust

    • European rules (ELV, WEEE, RoHS):  0.01wt% limit in electrical and electronic products and vehicles

    • European REACH:  Cd plate not permitted on many products, including vehicles; except aircraft, electrical contacts, and critical safety equipment

    Exposure
    Personnel may be exposed during manufacture, depot overhaul, and operational level touch-up and repair.

    • OEM and depot personnel may be exposed to Cd and As in liquids and mists used in plating and to Cr6+ in chromating processes.   Emission controls, PPE required.

    • Maintainers are exposed in corrosion control and localized touch-up (brush Cd).  PPE required.

    • Cd can be leached during washdown of systems containing Cd-plated components (e.g., engines), producing hazardous waste

    Alternatives, Applications, Status
    Various alternatives are in production for different military and commercial applications. All of these alternatives are commercially available with the exception of the LHE ZnNi.

    Most Common Cd Alternatives

    Examples of Authorizations and Implementations

    Specifications

    Corrosion-resistant (CRES) materials – stainless steels, Ti, composites

    Engine components, fasteners, connectors

    Various

    IVD Al (Ivadizing), pure evaporated Al

    Used by OEMs and several depots

    MIL-DTL-83488B

    Electroplated Al (AlumiPlate)

    F-22, F-35 landing gear and other structural components, connectors

    MIL-DTL-83488B

    Arc or flame sprayed Al

    Bombardier Dash 8

    MIL-DTL-83488B

    Metallic-ceramic coatings (e.g., SermeTel and equivalents)

    F-22 landing gear

    MIL-C-81751C

    Zn- and Al-filled spray and dip-spin paints and ceramics

    Commercial automotive fasteners

    Numerous automobile manufacturers

    Acid ZnNi

    Suitable only for low strength alloys (<160ksi)

    AMS 2417E

    LHE alkaline ZnNi

    Undergoing qualification testing

    None