If iron is covered with a more reactive metal such as zinc, even if the coating is damaged to reveal the iron, the zinc will continue to react in preference to the iron because the zinc is more reactive, and the exposed iron is not affected. The more reactive metal is sacrificed to protect the iron.
A good example is bolting blocks of Mg or Zn to ships’ hulls. These react with the saltwater, but are easily replaced. The steel hulls are protected.
No comments:
Post a Comment