Copper plating

What copper plating does

Copper is rarely the last layer on a part, because bare copper tarnishes in air. It does several jobs underneath other finishes:

• Underlayer. A copper layer helps nickel, silver and tin bond to steel and aluminium, and levels small surface marks before the next coat.
• Diffusion barrier. On brass, copper stops zinc from moving into a silver or tin top coat.
• Conductivity. Copper conducts electricity well, so it is used to make a part's surface conductive before a thin top coat, or on its own where it is protected.
• Heat-treatment stop-off. Copper plating masks areas of steel parts that must stay soft during carburising.

Strike and build-up

Copper is plated in two steps on most metals. A thin strike from a solution designed for adhesion goes on first, then a thicker layer from a faster plating solution builds up the specified thickness. Zinc die-castings and aluminium need their own pre-treatment before the strike.

Tell us the base material and we will confirm the pre-treatment and sequence.

What to put on your drawing or enquiry

• Base material and grade
• Copper thickness in µm, and the next layer if there is one
• Areas to plate or mask
• The plating specification and revision, if you work to one
• Quantity per lot and expected yearly volume

Specifications

Send the specification and revision with your drawing and we will confirm whether we can meet it.

Thickness measurement

Copper thickness is measured on our Fischerscope XRF instrument, including copper under a top coat of nickel, silver or tin.