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Galvanic Issues with Nickel-Plated Aluminum vs. Stainless?

Q. Hello,

I am designing a liquid cooling circuit that will use 60/40 EGW as the fluid.

I have a cold plate made out of Al-6061 & will be nickel-plated. I am trying to determine whether or not I can use stainless fittings without risk of galvanic corrosion?

The anodic difference between nickel & stainless is ~0.20V; between the stainless & aluminum it is ~0.40V.

My understanding is that in a "wet" environment (e.g. liquid cooling), it is best to try to keep the different to 0.15V or less?

Would I be able to use a corrosion inhibitor in the fluid to allow the safe usage of the aforementioned metal combinations?

Are there any concerns with the nickel plating wearing off during the thread engagement (e.g. friction) process?

Thanks.

Matt M.
- Atlanta, Georgia
August 20, 2024

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