The scientific definition of galvanic corrosion describes it as an electrochemical process in which two different metals or alloys come in electrical contact with each other in the presence of an electrolyte under the conditions of a corrosive environment, which leads to relative corrosion of both the materials in contact.
Rusting of iron is the most common example of galvanic corrosion, in which the core steel of the iron sheet is attacked and the protective coating of zinc is destroyed. Zinc being less noble is susceptible to the galvanic attack and once fully exterminated; it can cause the base metal to corrode very quickly. On the other hand, tin being more noble than the core steel makes it harder to break, but when it does, the underlying steel suffers the worst.