Galvanic Corrosion - How to prevent it

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I've noticed a couple of occasions recently on OcUK where galvanic corrosion has not been pointed out/warned about - So here's a brief snapshot of the issue.

You've spent a lot of money on your new loop, and want to keep it in pristine condition ? - Read on


What is Galvanic Corrosion ?

If you are new to watercooling, galvanic corrosion is not something make up by the PC watercooling industry to force you to buy their specialist fluids,
it has been recognised for hundreds of years effecting things such ships in the early Royal Navy.
I'm no chemist but in very laymans terms it is when very different metals react to each other when in contact via a fluid.This reaction causes one metal to start dissolving.
This diagram shows that the most common metals used in watercooling copper,brass and nickel are very similar and will work happily together.
But aluminium is at the other end of the scale so it won't play well with the others.
8Rxjao5.png

Extreme case of galvanic corrosion on a cpu block in a copper + aluminium loop

RqFFIH1.jpg


How can i prevent it ?

The easiest way to prevent Galvanic corrosion is to avoid aluminium, but you will still need to take precautions.
Do not just use distilled water or anything labelled as pure water/H20 - You still need an additive to help prevent any nasties from growing in your loop.
Additives / Inhibitors will drastically slow down any reactions - but this doesn't mean it will run for years without issues - you will still need to drain and replace your fluids every 12/18 months, or so, to be safe
Even the similar metals copper,nickel and brass will react together over time as they are different metals ( though in this case it is far slower and less extreme than having aluminium in there )


What fluid to use ?

For the sake of recommendations, i will use Mayhems . OcUK stock them and Mayhems are imo the best in the industry - they specialise in fluids.

4XwhtTr.png
Mayhems range of fluid and additives


X1 Clear and X1 coloured Premix Watercooling Fluid along with the Aurora 2 range contain multi metal inhibitors and can be used straight out of the bottle.

If you prefer to mix you own, then this is where it gets slightly complicated;

Ultra Pure H20 - This is a base liquid and needs an additive, such as XT-1 Nuke, as it is just 'pure' water.

If adding dyes to Ultra Pure H20, read the description. You are looking for '(GRAS) multi-metal inhibitors'

The Pastel/Aurora/X1 range of colour concentrated dyes have these included

The range just labelled 'Dye' do not have inhibitors so will require XT-1 Nuke


Aluminium

Seems that i've portrayed Aluminium as public enemy number 1, but remember Aluminium alone is not the problem. MIXING with other metals is the issue here.
Aluminium is lighter,cheaper and almost as good as conducting heat as the other metals i've mentioned, it just doesn't like company when watercooling.
EK have recently released a range of kits, prefixed with an A, that are 100% aluminium parts and i would have no problem recommending them ( just do not add your favourite 360mm copper radiator to the loop ).

jNxHBbj.png
EK watercooling kits



Hope i covered some things, and that this might help prevent any mis-haps in the future.


Disclaimer ;
This post is not endorsed by OcUK / Mayhems or EK - just 10 years+ of my own dabbling with watercooling
.


Additional info/FAQs

Thanks to ubersonic for these

I run an all copper loop, so i won't be effected ?

retailers don't usually seem mention it in specs these days (as most manufacturers don't) but most D5 pumps contain steel (and sometimes aluminium) so people can assume they have an all copper/brass loop when they don't. Secondly, copper/brass radiators are usually soldered together using tin, which as you're chart shows is most of the way to aluminium on the dissimilar metal scale.

I've seen AIOs' with mixed metal parts, how do they do it ?

AIOs, being sealed units can essentially get away with it because they will contain a special coolant that's designed to last for years even with aluminium and copper coexisting.

To put that in perspective, back in the early days of PC water cooling I once ran a mixed copper/alu loop for nearly four years without corrosion, because I used Toyota long life engine coolant which is designed for mixed metal loops and had a 5 year service life lol. Obviously doing that type of stuff isn't really a thing these days (because it would ruin clear blocks/tubing) but in a sealed AIO you can have whatever fluid you want.

 
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It would have made a lot more sense to say the way to prevent galvanic corrosion is to use metals of similar Anodic index, rather than say NOT aluminium and then retract and then say only aluminium.

JR
 
A brief but very informative guide. I guess this explains why the OcUK Tech Labs AIOs only have a 2 year warranty on them (copper plate and aluminium radiator). Do any other AIOs fall into this situation (Corsair, Coolermaster, Antec etc.)?
 
I guess this explains why the OcUK Tech Labs AIOs only have a 2 year warranty on them (copper plate and aluminium radiator). Do any other AIOs fall into this situation (Corsair, Coolermaster, Antec etc.)?

I would be amazed if any reputable company was selling a kit with copper block and aluminium radiator together.

Which OcUK kit are you reffering to ?
 
I would be amazed if any reputable company was selling a kit with copper block and aluminium radiator together.

Which OcUK kit are you reffering to ?

Unless I've misinterpreted "copper cold plate" and "aluminium heat exchanger", take your pick from these...

https://www.overclockers.co.uk/ocuk...-liquid-cooling-upgrade-bundle-bu-095-tl.html
https://www.overclockers.co.uk/ocuk...-liquid-cooling-upgrade-bundle-bu-096-tl.html
https://www.overclockers.co.uk/ocuk...-liquid-cooling-upgrade-bundle-bu-097-tl.html
https://www.overclockers.co.uk/ocuk...-liquid-cooling-upgrade-bundle-bu-098-tl.html
 
Standard Asetek spec isn't it? Just like the H105 which has a 5 year warranty...

Can't find any sources to confirm it's full aluminium, maybe just the fins, somebody buy one and cut it in half.

JR
 
Unless I've misinterpreted "copper cold plate" and "aluminium heat exchanger", take your pick from these...

Would have to agree with you there mate.

The 510LC from Asetek uses an alu plate and alu rad, but all the others use copper plate and alu rads, which is slightly concerning, if true, as Asetek are the OEM for the majority of the AIOs' on the market .

Can't find any sources to confirm it's full aluminium, maybe just the fins, somebody buy one and cut it in half.

JR

I had the same thought, alu fins with copper channels, but couldn't find anything to support this.
 
Awesome write up dude :)

Couple of additional notes I would point out, firstly retailers don't usually seem mention it in specs these days (as most manufacturers don't) but most D5 pumps contain steel (and sometimes aluminium) so people can assume they have an all copper/brass loop when they don't. Secondly, copper/brass radiators are usually soldered together using tin, which as you're chart shows is most of the way to aluminium on the dissimilar metal scale.


Do any other AIOs fall into this situation (Corsair, Coolermaster, Antec etc.)?
AIOs, being sealed units can essentially get away with it because they will contain a special coolant that's designed to last for years even with aluminium and copper coexisting.

To put that in perspective, back in the early days of PC water cooling I once ran a mixed copper/alu loop for nearly four years without corrosion, because I used Toyota long life engine coolant which is designed for mixed metal loops and had a 5 year service life lol. Obviously doing that type of stuff isn't really a thing these days (because it would ruin clear blocks/tubing) but in a sealed AIO you can have whatever fluid you want.
 
Might want to add a bit about ph levels too.

I found this out too late, I found out that I been running my loop too acidic. I was having problems with green sediment blocking my water blocks.

Mayhams x1 concentrate is 6-7 I think which I were you want it but in my loop it was 8.

A bit of bicarbonate of soda mixed in a cup and filtered has brought it down and I'm getting less sludge, Mayhams biocides will bring up.
 
I found this out too late, I found out that I been running my loop too acidic. I was having problems with green sediment blocking my water blocks.

Mayhams x1 concentrate is 6-7 I think which I were you want it but in my loop it was 8.
Actually acids have ph below 7 and 8 means moderately alkaline.
But also base is bad thing for some metals.
https://en.wikipedia.org/wiki/Water_cooling#Hydrogen
https://en.wikipedia.org/wiki/Amphoterism

But that green colour kinda hints to copper oxide.
 
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