Galvanized iron is coated with _______.

Explanation:

Commonly used metallic corrosion-resisting coatings:

• Hot dipping (galvanizing)
• Electroplating
• Cladding
• Metal spraying
• Cementation

Galvanizing:

• In this process, mild steel or iron is coated with zinc.
• For hot dip galvanizing, the workpieces are initially pickled in hot sulphuric or cold hydrochloric acid to clean the surface, and then fluxed with zinc chloride and ammonium chloride.
• After this they are dipped in molten zinc.
• Sometimes a small quantity of aluminum is added which gives a bright appearance and uniform thickness.
• The temperature of the zinc bath is usually maintained between 450° and 465°C.
• The hot-dipped workpieces are then quenched in a water bath.
• Galvanizing is done for structural work, bolts, nuts, pipes, and wires, which are exposed to different atmospheric conditions.
• This method is highly reliable.
• It can withstand severe working conditions and the cost is low.