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Mixing aluminium and copper?

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SwooshingRob

Member
Joined
Feb 6, 2004
Location
London
Mates,
In my wc system I will have copper blocks on the cpu and gpu and aluminium in the reservoir (waterchiller). Will this cause any electrolytical problems?

Cheers,
Rob
 
Yes, the copper + aluminium with tap water as the electrolyte will cause galvonic corrosion. However this can be pretty much avoided with the right water additives.

First make sure you are using distilled water (avaliable at most supermarkets etc) and also get some water additives like Zerax racing super- coolant or redline. Just about any racing coolant additive has anti - corrosive properties and should guard against the effects of mixing aluminium and copper. With the right mix of additives, nothing should happen.

http://www.dangerden.com/mall/Misc_Hardware/additives.asp

Has Zerax... should be easy to find in the UK as well.. I got some Hyber - Lube whilst I was in the US.. have not tested it yet though, bought it because of the awesome name.
 
If the aluminum is coated and you use an additive to resist galvanic corrosion you will have no problems. My reservoir is alum and have yet to see even a hint of corrosion in 2 years use now.
 
I can't put a coat of paint on the aluminium. It is an old stock P4 heatsink, acting as a chiller. It will be just about impossible to get paint into all those tiny places.
I've got some water-wetter I was planning to use. If I understand ShadowCat correctly, this will be just fine as an anti-corrosive. The water is coming from my dehumidifier.

It was a long time since I studied chemistry, so correct me if I'm wrong, but after some thinking I came up with this conclusion:
The galvanic reaction that will take place will move atoms from the aluminium heatsink to the copper water blocks, right? So eventually the heatsink will disappear and my waterblocks will have a thick layer of aluminium on the inside. As this layer gets thicker and thicker, the temperatures will raise. Since this process is significantly slowed down by using an anti-corrosive, I can expect only minor (if any) differences in temperature after a year or so.

Is this correct?
 
It is really hard to get a good coating, even anodization can be coroded through sometimes. Maybe you should consider purchasing a cheap copper heatsink.


Jon
 
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