What metal is usually employed as a sacrificial anode for corrosion control purposes?

Zinc is commonly used as a sacrificial anode for corrosion control due to its electrochemical properties. In galvanic corrosion processes, zinc has a more negative electrochemical potential compared to most other metals, which allows it to corrode preferentially. This ensures that the protected metal, often steel or iron, remains intact by providing a path for corrosion to occur on the zinc instead.

When zinc is connected to a metal structure in a corrosive environment, such as buried pipelines or ship hulls, it effectively sacrifices itself to protect the more valuable metal. This method is often referred to as cathodic protection, where the sacrificial anode improves the longevity and integrity of the metal it protects by redirecting corrosive activity toward itself.

In contrast, iron, copper, and aluminum are less commonly used as sacrificial anodes. Iron would corrode too quickly in most environments and would not provide adequate protection. Copper, being less reactive than zinc, is generally used in different applications and can also contribute to corrosion if used in conjunction with other metals. Aluminum can serve as a sacrificial anode but is less frequently chosen due to its properties and performance in various environments compared to zinc.