Metallic materials in contact with different environments suffer a decline for the passage of their elements combined with environmental substances. This decline is called corrosion

Types of corrosion

wet: when metallic material is in touch with an environment containing water

dry: when environment is made of gaseous atmosphere, usually with high temperature

wet: electromechanical type (galvanic), where the corrosion process is the result of an anodic process attacking metallic material, coupled with a cathodic process. As a consequence corrosion processes in WET conditions follows rules of thermodynamics.

dry: chemical type, corrosion processes are subject to rules of thermodynamics and of chemical kinetics.

Uniform or general corrosion: all the metallic material’s surface is uniformly involved, so very predictable (rare case)

Located corrosion : corrosive processes are shown on some parts of the metallic material’s surface with particular morphologic aspects.

Selected corrosion: by attack of particular constituents of metallic material (alloy from more or less noble metals).

“During a corrosive process, for any type mentioned, metallic material suffers a loss of mass in any case”.