Galvanic Corrosion

Galvanic corrosion occurs when two metals are placed in electrochemical contact in the presence of an electrolyte.

This then results in corrosion of the less resistant of the metals in question (anodic/anode), while the stronger; more noble cathodic metal will corrode much slower.

Seeing the image listed below, the table provides an insight as to where this can occur:

Galvanic_Corrosion_Chart