What occurs during oxygen pitting?

Oxygen pitting specifically refers to a localized form of corrosion that can lead to the formation of small pits or holes in a metal surface, often as a result of oxygen being present. When free oxygen comes into contact with a metal surface, especially in the presence of moisture or an electrolyte, it can lead to the accumulation of corrosion products.

In this scenario, as the corrosion progresses, these products may form a sort of barrier or "cap" over an area of the metal surface. This cap can enclose a bubble of oxygen. The corrosion underneath the cap can continue due to the electrochemical reactions taking place, which can contribute to further pit formation. This process creates localized corrosive environments that can significantly weaken the metal.

Understanding the mechanics of oxygen pitting is crucial as it often occurs in equipment and components where oxygen is present, especially in the presence of water or humidity. Recognizing the phenomenon helps in implementing proper preventive measures, such as applying protective coatings or controlling the environmental conditions to mitigate corrosion.