Answer to Question #149226 in General Chemistry for eddy

Question

explain differential aeration corrosion

Answer 1

Differential Aeration Corrosion takes place when there is an uneven supply of oxygen to areas of the same metal component. It is a type of electrochemical corrosion that affects metals such as steel and iron. When a poorly oxygenated area is adjacent to an area with a good supply of oxygen, an anodic/cathodic reaction occurs. Oxygen screening, crevice corrosion and poultice action are other terms for this type of corrosion.

The reaction occurs because

oppositely charged electrons flow between the smaller anode and larger cathode. Positively charged cations meeting negatively charged anions forming corrosion product and a resulting pit in the metal, otherwise known as pitting corrosion. In a gutter, pipe, tank or similar the anode is just below the waterline. This is where the oxidation occurs, corrosion product forms and a pit develops weakening the metal.