Corrosion

Corrosion is a natural process, it converts a refined metal to a more chemically-stable form, such as its oxide, hydroxide, or sulfide. Corrosion is a dangerous and extremely costly problem. Because of it, buildings and bridges can collapse, oil pipelines break, chemical plants leak, and bathrooms flood.this means electrochemical oxidation of metal in reaction with an oxidant such as oxygen or sulfates.  General corrosion occurs when most or all of the atoms on the same metal surface are oxidized, damaging the entire surface. Most metals are easily oxidized: they tend to lose electrons to oxygen (and other substances) in the air or in water. Corrosion can also occur in materials other than metals, such as ceramics or polymers.Corrosion degrades the useful properties of materials and structures including strength, appearance and permeability to liquids and gases.Many structural alloys corrode merely from exposure to moisture in air. There are various ways of protecting metals from corrosion (oxidation) including painting, hot dip galvanizing, and combinations of these.All metals can corrode. Some, like pure iron, corrode quickly. Stainless steel, however, which combines iron and other alloys, is slower to corrode and is therefore used more frequently.All small group of metals, called the Noble Metals, are much less reactive than others. As a result, they corrode rarely.



Soorce: wikipedia,electrochem.org,thebalence.com