Which type of metal is more likely to act as the anode in galvanic corrosion?

The type of metal most likely to act as the anode in galvanic corrosion is reactive metals. In galvanic corrosion, two different metals are in electrical contact in the presence of an electrolyte, leading to a galvanic cell that causes one metal to corrode faster than the other.

Reactive metals, which have a higher electrochemical potential, are more susceptible to oxidation and lose electrons more readily than the more noble metals. This behavior means they will corrode and act as the anode in this type of corrosion process. For example, metals such as zinc or magnesium, which are considered reactive, will sacrifice themselves to protect less reactive metals like steel or copper from corroding.

On the other hand, noble metals are less likely to undergo corrosion as they have a strong resistance to oxidation and a lower tendency to act as anodes. Pure metals and alloys can vary in behavior, but typically they don't exhibit the same high reactivity as the reactive metals, making them less likely to serve as an anode. Thus, reactive metals are the ones that will preferentially corrode and serve this role in a galvanic environment.