The corrosion which is brought about through ionic reaction in presence of moisture or solution as a conducting medium is called (wet) electrochemical corrosion or immersed corrosion as it occurs where they are immersed in the solution.
Essential are:- i) The formation of anodic & cathodic part ii) Presence of a conducting medium. iii) Corrosion of anodic part only. iv) Cathodic reaction can take place in two ways, I) By H2 evolution II) By O2 absorption v) Formation of corrosion product between anode and cathode.
ii) Absorption of Oxygen: