Calculating galvanic current

[kevlar49]

I have a situation where there are two dissimilar metals in contact with each other. They will be exposed to cryogenic temperatures, so there is a possibility of moisture wetting. I know the approximate potential in sea water service. I was looking for a way to conservatively estimate the galvanic current given the exposed surface areas. I don't know the polarization resistance.

 

[EdStainless]

What would they be wetted with? Condensate?
The conductivity of the fluid matters when you are dealing with very low potentials.
Or will the outside be seeing condensation from a contaminated atmosphere?


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P.E. Metallurgy, Plymouth Tube

 

[kevlar49]

condensate from a possible launch site where marine mist is possible.

 

[EdStainless]

So if you don't seal these places where different materials meet then it will be akin to soaking them in seawater.
You need to look at how to eliminate crevices.
What are the materials involved?

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P.E. Metallurgy, Plymouth Tube

 

[kevlar49]

Plug made of 316 screwed into housing of 6061 aluminum but with Inconel X750 boss seal in between. Surface area ratio might be favorable.I might be able to leave this in if I have a sufficiently low galvanic current according to the NASA standard 6012 referenced.