Galvanic corrosion between Inconel 625 and Super duplex

[aleks6561]

Hello! Are there anyone som have some documented experience or relieable sources, good or bad, with electrical connection between 25% Cr super duplex and Inconel 625? Offcourse they have different galvanic potential, but enough to cause severe corrosion problems? The system is in sea water, with no cathodic protection. Design life typical 20 years.

 

[cloa]

What is the approximate surface areas of the metals? Is this immersed in well oxygenated sea water?

 

[aleks6561]

Assume well oxygenated. Assume bad conditions for surface areas (small anode and large cathode).

 

[EdStainless]

They are so close I don't see any concern. Since both alloys rely on a chrome oxide passive film they should respond very similar.
Now crevice corrosion may be another mater. It would not surprise me if the 625 was the first to go.

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