I suggested Nickel because it's not too far from copper, on a galvanic chart. Chrome is a bit too far, for a good solution:
http://www.engineersedge.com/galvanic_capatability.htm
Nickel is just about ideal, and quite feasible. If you go that route, I'd recomend contracting this out, and make sure that you tell them that it's an anti-corrosion coating; they should know what to do.
Let me know how it turns out; I have no idea how much they charge, but I've also got a piece to do.