What exactly is the Sacrificial Method in terms of Corrosion?

-Placing a more Reactive Metal with the other Metal that you won't want to Corrode will work because: -The Reactive Metal will react with the Water and Oxygen, instead of the other Metal. -Example may be with Magnesium being Bolted onto Lesser Reactive Metals; since Magnesium wants to lose its Electrons more than the other Metal, it will React with the Oxygen and Water -This is seen in Ship Hulls, or Underground Pipes