Electrochemical Kinetics of corrosion

Corrosion is thermodynamically possible for most environmental conditions, but thermodynamic tell us nothing about how it fast (rate of corrosion), while chemical kinetics is a study of the rate of reaction.

Electrochemical reaction either produce or consume electrons, thus the rate of electron flow to or from a reacting interface is a measure of reaction rate.
Electrons flow conveniently measured as current, I in ampere where 1-ampere is equal to 1- coulomb of charge (6.2 × 1018 electrons) per second.
The proportionality between I and mass reacted, m , in electrochemical reaction is given by Faraday s Law.

A conducting metal containing mobile electrons forms a complex interface in contact with n aqueous solution. unsymmetrical polar H2O molecules ( H-atom positive , O-atom negative ) are attracted to the conductive surface , forming an oriented solvent layer , which prevents close approach of charged species (ions) from bulk solution. Charged ions also attract their own sheath of polar water-solvent molecules which further insulate them from the conducting metal.