What Does Corrosion Current Mean?
A corrosion current is the current produced in an electrochemical cell while corrosion is occurring. Electrochemical corrosion involves the transfer of electrons from the anode to the cathode. This flow of electrons from the electronegative region to the more electropositive region generates an electric current in the system. The loss of electrons at the anode subsequently triggers oxidation reactions that cause the anode to deteriorate (corrode), while the cathode remains unaffected.
Corrosionpedia Explains Corrosion Current
The driving force for the flow of electrons is the difference in potential between the anode and the cathode. This process is most evident in the corrosion between two dissimilar metals (also known as bimetallic corrosion).
When a metal is immersed in a liquid (electrolyte), it adopts an electrode potential (also known as corrosion potential). The variance in potentials between the two metals results in a potential difference, which is responsible for the movement of electrons from the anode to the cathode.
The magnitude of the corrosion current in the system is proportional to the potential difference. That is, the greater the potential difference, the greater the corrosion current generated, and therefore the more severe the rate of corrosion at the anode.