Metal finishing Q&As since 1989

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Electroplating over graphite coatings

Q. Dear Sir:

Can I plate copper over a graphite-based (pretty conductive) coating? By which method?

Thank you,

Itamar Mazaki
- Rehovot, Israel
2001

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You can coat your graphite layer as long there are no inhibiting organic additives left in that said layer. If you carbon coated your substrate with a graphite solution containing organic additives, this might disturb your subsequent metal plating. Therefore, there are many aqueous processes to coat conductive carbon black or graphite on non-conductive substrates which provide a starting layer for your electrodeposition. If the areas to plate are too large you will run into the situation that your "metal front" growing on your carbon layer will grow too slow and the exposed graphite layer might dissolve in the acidic electrolyte.

Regards,

Christoph Hagg
- Graz, Austria
2001

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We do that. We are plating machined surfaces which are not allowed to get dirty (no coolant and vacuum extraction to remove dust). We quickly brush off loose graphite with water and toothbrush and dry thoroughly (an oven at 50 degrees for an hour or so). We can then electroplate directly (in copper pyrophosphate). The copper is held in place by mechanical interlocks. You must avoid the graphite soaking up water and especially plating solution... it is a porous material.

We once tried stripping copper from graphite but the solution trapped within the graphite electrolysed and fragmented the material.

Robert Chilton
- Chester, UK
2001