Which type of metal is typically used as a sacrificial anode?

The use of a less noble metal as a sacrificial anode is based on its ability to corrode preferentially when placed in an electrochemical environment. In corrosion protection, sacrificial anodes are intentionally made from metals that are more reactive than the metal of the structure they are intended to protect. This type of anode oxidizes instead of the protected metal, thereby preventing corrosion.

When a less noble metal (such as zinc, magnesium, or aluminum) is connected to a more noble metal (like steel), it acts as a sacrificial material by corroding and releasing electrons. These electrons provide the necessary current to keep the more noble metal in a reduced state, significantly slowing down or even stopping its corrosion.

In the context of corrosion and electrochemistry, less noble metals have a higher tendency to lose electrons compared to more noble metals, making them suitable for this purpose. Their placement in systems such as pipelines, ships, and tanks serves to extend the lifespan of the more valuable structures made from more noble metals.