Mechanism and General Information

Barrier coatings protect steel against corrosion by reducing the permeabihty of liquids and gases through a paint film. How much the permeabihty of water and oxygen can be reduced depends on many factors, including  

Pigments used for barrier coatings are diametrically opposed to the active pigments used in other anticorrosion coatings in one respect in barrier coatings, they must be inert and completely insoluble in water. Commonly used barrier pigments can be broken into two groups  

In the second group, care must be taken to avoid possible electrochemical interactions between the metallic pigments and the metal substrate [109]. 

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