Corrosion
Corrosion is the breakdown of materials due to chemical reactions. It is usually oxidation with air molecules and often in the presence of water. Corrosion also occurs when an acidic/basic corrosive substance touches another material. When a material corrodes, its physical properties change. Problems with corrosion are mostly with metal, though other materials can corrode. Corrosion is a form of erosion. Some materials, such as stainless steel, are highly resistant to corrosion. Metals that may corrode can be protected by plating, painting, and other means.
One form of high temperature corrosion can lead to the formation of compacted oxide layer glazes, which under certain circumstances reduces wear.
Iron corrosion is called rusting.
Corrosion Media
Corrosion on exposed metal, including a bolt and nut
Riveted connection of elements of the cooling tower of a power plant from 1904. Increased material volume caused by corrosion.
Galvanic corrosion of an aluminium plate occurred when the plate was connected to a mild steel structural support.
Gold nuggets do not naturally corrode, even on a geological time scale.
Diagram showing cross-section of pitting corrosion
Normal microstructure of Type 304 stainless steel surface
Sensitized metallic microstructure, showing wider intergranular boundaries
Corrosion in the crevice between the tube and tube sheet (both made of type 316 stainless steel) of a heat exchanger in a seawater desalination plant
The US military shrink-wraps equipment such as helicopters to protect them from corrosion, thus saving millions of dollars
Galvanized surface
