Question

State the property of the metal being used in the following processes:

Use of Metal	Property
Aluminium in thermite welding
Zinc in galvanization

Answer 1

1) Thermite welding is a chemical welding process in which an exothermic reaction is used to supply the essential heat energy.

• In thermite welding, a mixture of aluminium powder and iron powder is used.
• Aluminium has a greater affinity for oxygen than iron and the reduction with aluminium is highly exothermic and generates sufficient heat to melt the meal.

Hence, aluminium is a good reducing agent.

2) In galvanization, iron is covered with a protective layer of zinc to prevent the iron from rusting because zinc oxidized itself when exposed to air and water.

Use of Metal	Property
Aluminium in thermite welding	Aluminium is a good reducing agent.
Zinc in galvanization	Zinc oxidises more readily than iron to prevent rusting of iron.