Posted: Jan 10, 2018 12:57 pm
by zulumoose
What he has there is a stack of dissimilar metals with an electrolyte between them. It is the same thing as a battery, and the magnetism is a smoke screen, not required at all except it helps clamp it together.

There is an induced voltage between many different materials, which results in galvanic corrosion. No mystery at all. You can look up a table of the induced voltages in any 1st year materials science textbook.

Clamp aluminium and iron together, and you can measure a voltage. Even raw aluminium and stainless steel will corrode each other if clamped together with a conductive electrolyte.

This is how sacrificial anodes work as well. Put a block of the right metal on a steel construction and the natural corrosion will concentrate there, reducing corrosion on the important parts.