silver and copper alloy
The most common work-horse material in the electrical industry for more than a century is copper, because of its excellent electrical conductivity, thermal conductivity, resistance to oxidation, and corrosion-resistance. These properties make it a highly desirable base material for a variety of applications including electrical switchgear, connectors, and terminals.
Many different types of copper alloys are available to suit a wide range of design requirements. Each alloy has its own specific characteristics, including hardness, machinability, strength, aqueous corrosion resistance, solderability and mechanical properties.
A few of the most commonly used copper alloys include C101, C110, and C145. The first two are relatively straight-forward and can be plated directly without the need for any pretreatments. The latter two must be treated with an alkaline cleaning or acid pickle to remove any oxides that may prevent the copper from achieving a clean surface that is ready for silver plating.
The next step is to plate the parts with a nickel underplate if desired; this helps to provide a solid, rigid structure that will allow the silver layer to be deposited onto. This increases load/bearing durability and can help extend the shelf-life of the silver layer in high contact pressure switching or wear applications.
A heavy nickel underplate also improves the corrosion performance of the silver layer as it limits deposit porosity. This reduces the need to increase the silver thickness and allows for more effective corrosion protection with less cost impact.