Electroplated cadmium is a robust and versitile metallic coating. Cadmium is a soft white metal that, when plated onto steel, cast iron, malleable iron, copper, and powdered metal, 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, yielding the familiar gold color as seen in the above picture. Other colors, such as olive drab and black are also available.
Cadmium plating offers an exceptional bonding surface for adhesives, such as those increasingly used in aircraft manufacturing, and is the preferred coating for salt-water environments. Additional advantages of cadmium plating include: low electrical resistance; outstanding conductivity; superior solder-ability; favorable galvanic coupling with aluminum; and excellent natural lubricity, which results in prevention of galling and a low coefficient of friction. Furthermore, the corrosion products of cadmium are less significant that those of other plated coatings such as zinc. These characteristics are especially useful in applications where components will be repeatedly disassembled and reassembled, such as in scheduled maintenance of aircraft. Thus cadmium plating continues to be critical to the aerospace industry. Cadmium plated surfaces resist mold or bacteria growth.