Pitting corrosion is primarily a wet corrosion process. It occurs in the presence of an electrolyte, typically water containing chloride ions or other aggressive anions. The localized breakdown of the passive protective layer on the metal surface leads to the formation of small pits or cavities.
Key Points:
Wet Process: Requires the presence of a liquid electrolyte, such as seawater, de-icing salts, or acidic solutions.
Localized Attack: Pitting corrosion is highly localized, creating deep, narrow pits that can penetrate the metal.
Environment: Common in marine environments, chemical processing industries, and areas with high humidity or salt exposure.
Understanding that pitting corrosion is a wet process helps in designing appropriate preventive measures, such as proper drainage, application of protective coatings, and use of corrosion-resistant materials.