Why can Magnesium prevent the corrosion of iron and steel?

Question

the Mg are used in pipelines and ship bottoms to prevent corrosions....but i just dont get why...

Answer 1

The ingot of Mg are called sacrificial anodes. It is like adding a tub of icecream to a haystack. You prefer to eat the icecream and leave the hay alone (until the icecream is gone!). The corrosive environment can tell when the Mg is gone because because of the change in availability of electrons, sort of like using up a battery. Hope that helps a little.