Electrochemical corrosion is a spontaneous process that always denotes the existence of an anodic zone (the one that undergoes corrosion), a cathodic zone and an electrolyte, and the existence of these three elements is essential, in addition to a good electrical connection between anodes and cathodes, so that this type of corrosion can take place.
The most frequent corrosion is always of an electrochemical nature and results from the formation on the metal surface of a multitude of anodic and cathodic zones; If the metal is not submerged or buried, the electrolyte is condensed water from the atmosphere, for which the relative humidity must be 70%.