At customers’ request steel products can be copper-plated before a chrome layer is applied. This provides the product with better protection against corrosion. However, after being copper-plated the product needs to be re-polished. Previously, copper was often used as undercoat for the chrome layer. Nowadays, a duplex nickel layer is applied, as this offers even better protection against corrosion under most circumstances.
Copper is especially suited for use as an undercoat for chrome-plating on casted zinc alloy (sumac). The copper layer can also be used as a decorative layer, which can be aged artificially. A copper layer is not chip-proof. Any other top layer can be applied on top of a copper layer.