Question

In which process is a protective zinc coating applied on iron to prevent it from rusting?
1. Galvanisation 
2. Annealing
3. Smelting
4. Welding

Answer 1

Correct Answer - Option 1 : Galvanisation 

The correct answer is " Galvanization ".

• Galvanization is the process of applying a coating of zinc to steel or iron. 
• This is done to protect steel and iron from the process of rusting.
• The most common method of galvanization is " hot-dip-galvanization".
• In this method, parts are submerged in a bath of molten hot zinc.

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• Annealing is a heat treatment process used mostly to increase the ductility and reduce the hardness of a material.
• Smelting is a form of extractive metallurgy to produce a metal from its ore.
• Welding is a fabrication process whereby two or more parts are fused together by means of heat, pressure or both forming a join as the parts cool. 

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• When zinc is coated on iron or steel,  it protects corrosive substances from reaching the underlying steel or iron. 
• The electroplating such as chromate conversion coating is applied to provide further surface passivation to the substrate material.
• The hot-dipping method is not applicable to the materials that are constantly exposed to acid and acid rains.
• It is also not applicable to bolts and nuts.