Galvavic corrosion What is the chemical compound of Aluminum/Stainless steel corrosion?

Dale:

That depends on the chemical environment, although often it would be an aluminum oxide.

Aluminum is more active than other metals. If you couple it to stainless steel, then it will corrode (become an anode) in preference to the adjacent stainless steel (cathode) which will be prevented from corroding. The worst situation for galvanic corrosion is having a small area of aluminum connected to a large area of stainless steel.

This is briefly mentioned in the Alubook "How to avoid or minimize galvanic corrosion", Topic 11065. See:

Click the arrows> to go either back or forwards in the topic.

In the UK the National Physical Lab (NPL) has a good general discussion of galvanic (bimetallic) corrosion in the Guides to Good Practice in Corrosion Control series in a big 579K file at

Also see the comprehensive lectures on aluminium, including corrosion, in the Talat series. Go to and then download sections 1252, 5103, 5104, etc.

Pittsburgh Pete

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