Cathode contamination conclusions

In conclusion, the atmospheric corrosion of steel involves two distinct surface states, wet and dry, which differ in terms of anodic and cathodic partial reactions taking place. The average rate of corrosion depends above all on the action of humidity cycles and it is accelerated by the presence of sulfates and other anionic contaminants. By forming an electrolyte these permit the creation of corrosion cells between the cathodic and anodic sites in the porous rust that covers the surface. 

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