Galvanic corrosion typically occurs on which type of substrate?

Galvanic corrosion occurs when dissimilar metals are in electrical contact with each other in a corrosive environment. In this context, steel is often used in construction and is commonly coupled with other metals. When steel is paired with more noble metals (like copper or aluminum) in the presence of an electrolyte, such as water, an electrochemical reaction can take place. In this reaction, the less noble metal (in this case, steel) will corrode preferentially, leading to significant deterioration of the steel substrate over time.

This phenomenon can frequently be observed in various applications, such as pipelines or marine environments, where steel is in contact with other metals and exposed to moisture. The characteristics of steel, including its electrical conductivity and widespread use, make it particularly susceptible to galvanic corrosion when coupled with more noble metals.

Understanding galvanic corrosion is essential for coatings inspectors, as preventing corrosion often requires careful selection and isolation of materials to avoid creating galvanic cells. Dissimilar metals should be prevented from being in contact, or appropriate coatings must be applied to isolate them from each other and from corrosive environments.