Chemical Corrosion Vs Electrochemical Corrosion

Chemical Corrosion	Electrochemical Corrosion
It occurs in dry conditions.	It occurs in wet conditions such as presence of electrolyte or moisture.
It takes place by direct chemical attack of atmospheric gases such as O2, CO2, Cl2, H2S, SO2.	It takes place by electrochemical attack of corrosive environment on the surface of metal. This involves setting up of a large number of galvanic cells.
It takes place on homogeneous and heterogeneous metal surfaces.	It takes place on heterogeneous metal surfaces only.
Corrosion product is formed at the place of corrosion.	Corrosion takes place at anode but corrosion product is formed near cathode.
Corrosion is uniform.	Corrosion is non-uniform. When anodic area is small, pitting corrosion takes place more frequently.
It is a slow process.	It is a fast process.
It involves chemical reactions of atmospheric gases.	It involves electrochemical reactions.