Corrision prevent entery ofwater and air into metal or any substance and metal safe from rusting.

Advantages of corrosion:\t\xa0Surface corrosion forms an oxide layer. It acts as a barrier for air and moisture and thereby preventing the inner metal from corrosion.\tSome metals like zinc act as sacrificial anodes to prevent corrosion to other metals.\tGalvanic corrosion is the principle that is used in batteries. Here, two metals carbon and zinc are intentionally mixed together in a electrolyte solution where zinc corrodes faster in order to generate electrical charge.