A refined metal is changed into a more chemically stable oxide by the natural process of corrosion.
It is the gradual deterioration of materials (often a metal) by chemical or electrochemical reaction with their environment.
The corrosion of iron generally called rusting.
Galvanic Corrosion
When an electrolyte and two metals with differing electrode potentials come into contact with one another, one of the metals acts as a cathode and the other as an anode.
As a result, the anode dissolves into the electrolyte as a result of an electrochemical process.
This electrochemical process is called galvanic corrosion of metals.
A cathodic metal can be protected from corrosion by using galvanic corrosion.
Only in the presence of an electrolyte that may provide a path for the movement of ions and an electric conducting path between the metals does galvanic corrosion take place.
The use of zinc in batteries to promote corrosion and produce a potential difference is one example of the galvanic corrosion.
