Let metal sit surrounded by oxygen for a while and the metal will corrode. Corrosion is the chemical reaction that takes place when a metal is in contact with oxygen. The metal reacts with the oxygen to form a compound called an oxide on the surface of the metal. The metal becomes tarnished and loses its shine. Metals high in the reactivity series (an observable series of metals, in order of reactivity from highest to lowest) corrode more quickly than less reactive metals. Simply put corrosion is the process by which a metal is worn away as its surface reacts with oxygen and other chemicals. Corrosive (a form of corrosion) is a term describing a substance, usually a strong acid that burns away skin or the surface of an object. The chemical formula for corrosion as rust is Fe2O3.nH2O. There is a process by which the formula becomes Fe2O3.nH2O, and that formula is 1.2Fe(s) + 2H2O(l) + O2(g) ==> 2Fe2+(aq) + 4OH-(aq)
2.Fe2+(aq) + 2OH-(aq) ==> Fe(OH)2(s)
3.Fe(OH)2(s) =O2=> Fe(OH)3(s)
4.Fe(OH)3(s) =dehydrates=> Fe2O3.nH2O(s) or rust
Corrosion can be defined as the degradation of a material due to a reaction with its environment. Degradation implies deterioration of physical properties of the material. This can be a weakening of the material due to a loss of cross-sectional area, it can be the shattering of a metal due to hydrogen embrittlement, a process by which various metals, most importantly high-strength steel, become brittle and fracture following exposure to hydrogen, or it can be the cracking of a polymer due to sunlight exposure. Materials can be metals, polymers (plastics, rubbers, etc.), ceramics (concrete, brick, etc.) or composites-mechanical mixtures of two or more materials with different properties (Corrosion Technology Laboratory).
All metals corrode, but corrosion can be prevented. Corrosion happens on the surface of most metals. Iron (from which steel is made) corrodes easily, but it is very strong and...