This is where the science comes in. Galvanic corrosion, occurs when two dissimilar metals i.e. mild steel and stainless steel, aluminium and steel and the like, are in contact with each other in the presence of an electrolyte (like moisture or a conductive liquid, salt water, acid rain ). This causes an electrochemical reaction where one metal corrodes much faster than it would alone, while the other metal is protected from corrosion.
The moral of the story is NEVER mix raw material in a finished product, much better to make all the finished item in the same raw material.
The photo shows galvanic corrosion in its worst form, even plastic coated galvanised wire corrodes when clipped using stainless steel clips a small chink in the plastic allows the electrochemical reaction between the stainless steel and galvanised wire resulting in corrosion and ultimate failure of the wire but the stainless steel is hardly tarnished
