Doesn't that refer to electrolytic corrosion, ie corrosion between two metals with different electrical charges? (or was it just dissmilar metals?)
I've seen magnesium cathode/anode(?) radiator caps that supposedly prevent corrosion by sacrificing the magnesium slug instead of the cooling system parts.
The problem with this principle when applied to the whole car is that rust is caused by iron in the steel reacting with oxygen in water or the air, not a reaction between two metals involving electrical charges.