Donna,

Plate the gold over the nickel. The nickel deposit serves
two purposes. First, it acts as a barrier, preventing
diffusion of the copper into the gold. A second but not
often recognized advantage of gold over nickel is the
"brinelling effect" whereby a thin layer takes on the
physical characteristics of the substrate, In your
application, the harder nickel makes the softer gold more
durable.

Regards,

Dan Brandler.

Donna Perry wrote:

> If we want a board to be gold plated .00003 to
> .00005 thick, can it be done over electro-plated
> copper or must nickel be applied first?
>
> DPerry