Thanks for the reply
It's a computer heatsink. I've posted simliar questions on PC related forums, but I wasn't getting very far.
From the manufacturer's website:
Here are some pictures of my particular heatsink:
Rust on the bolts that hold the fins together.
As you can see, the copper is in contact with the aluminium. I don't know how difficult it would be to remove the bolts and take it apart. This would also create an uneven base, as the fins wouldn't line up exactly as they where before. I would have to lap the base after reassembly. This is why I want a method of coating the aluminium and copper at the same time.
Typical operating temperatures are between 20'C and 55'C, relatively low I would guess. I live near the coast, so there's more salt in the air than usual. Also the humidty is quiet high. I live in Durban, South Africa.
How well does anodizing prevent corrosion? I have a few heatsinks that are anodized and they show no signs of corrosion, so I'm guessing pretty well?
And if there is a way to get it electroplated, which metal is the best option? Silver's heat conductivity is very good but how quickly would it corrode/tarnish? Would nickel be a better option?