What is sacrificial protection in metal treatment?

Sacrificial protection involves coating a metal with a more reactive metal to prevent corrosion. This technique works on the principle of electrochemistry, where the more reactive metal acts as a sacrificial anode. When the two metals are in contact in the presence of an electrolyte, the more reactive metal oxidizes preferentially, protecting the less reactive metal from corroding. This is commonly seen in applications such as galvanization, where steel is coated with zinc. The zinc corrodes instead of the steel, thus preserving the integrity of the underlying metal structure.

This method is particularly effective for metals that are prone to rusting, as it provides a long-term protective measure that extends the life of the metal object in harsh environments. This contrasts with the other options, which may involve preventive measures against corrosion but do not utilize the concept of a more reactive metal protecting a less reactive one.