Question

Why galvanised articles protect against rusting even after the zinc coating is broken?

Answer 1

because zinc is very reactive so when the moisture or air comes in contact with that article, the zinc reacts with the moisture and air first and forms zinc oxide and zinc hydroxide and hence protect the article from corrosion. hope it helps

Answer 2

because glavanished articles is resistance of water and air so if prevent the rusting that is caused by air and water