ABSTRACT
The metallic state is in most metals an unstable condition resulting from the smelting operation, in which energy is imported by the ore as the metal is derived. After extraction, most metals undergo a slow deterioration process during which they shed this energy and return to a more stable condition in which they are combined with some element of their environment, such as an oxide, a sulfide, or some other corrosion product. This energy conversion process is known as corrosion.
