Which metals are commonly used as sacrificial anodes to protect buried steel structures from corrosion?

The correct response identifies zinc and magnesium as the commonly used metals for sacrificial anodes in the protection of buried steel structures from corrosion. This practice is rooted in the concept of galvanic protection, where a more reactive metal is placed in electrical contact with a less reactive metal (like steel).

Zinc is widely employed due to its high electrochemical potential, which allows it to corrode preferentially, creating a protective layer for the steel structure it is intended to safeguard. Similarly, magnesium serves as an effective sacrificial anode because of its strong anodic behavior, which allows it to corrode in place of the steel, thus preventing rust and structural degradation.

While other metals like iron and aluminum can also undergo corrosion, they do not provide the same level of protection when used as sacrificial anodes. Copper, although it has some corrosion-resistant properties, is generally not used as a sacrificial anode because it is less reactive compared to zinc and magnesium.

In summary, the practice of using zinc and magnesium as sacrificial anodes is an effective corrosion prevention strategy for buried steel structures, allowing these anodes to corrode in place of the steel, effectively extending the life and integrity of the structure.