How does corrosion work
How does corrosion work
Electrochemical corrosion is the most important
classification of corrosion.
Four conditions must exist before electrochemical corrosion can proceed:
(1) there must be something that corrodes , the metal
anode, where the oxydation reaction take places
(2) there must be a
cathode, where the reduction reaction take
places
(3) there must be continuous conductive liquid path (electrolyte, usually
condensate and salt or other contaminations), for example:
water, seawater, condensing water, humidity..
(4) there must be a conductor to carry the flow of electrons from the anode to
the cathode.
This conductor is usually in the form of metal-to-metal contact such as in
bolted or riveted joints.
The elimination of any one of the four conditions will remove
the conditions that causes corrosion.
An unbroken (perfect) coating on the surface of the metal will prevent the
electrolyte from connecting the cathode and anode so the current cannot flow.
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