Explain the advantages of galvanizing over tinning.
Metallic coatings are either anodic or cathodic depending upon the electrode potential of base method & coating metal. They are used for the prevention of corrosion of metals.Metallic coatings can be divided into anodic and cathodic coating. Galvanising is a coating of Zinc over iron,here zinc acting as anode and exposed area of iron acting as cathode. It means area of anode is larger. Comparatively in tinning coating of tin is acting as cathode(large area)and exposed area of iron(small) acting as anode. Here area of anode is small therefore corrosion will be faster in tinned article as compared to galvanized article. Therefore,galvanizing is more preferred than tinning.