Explain how,reduction reaction of aluminium can be used for welding cracked machine parts of iron.Give the reaction involved.
Answers
The thermite welding or thermic welding is the process of welding the joints of iron using thermit reaction.
Thermit reaction is the reaction of metal oxide with the aluminum. The aluminum acts as a reducing agent and the reaction is highly exothermic and hence called a thermite reaction.
The aluminium reduces the oxide of another metal, most of the times, it is iron oxide (FeO) because aluminium is highly reactive. The reaction involved can be shown as:
Fe2O3 + 2Al → 2Fe + Al2O3
The Aluminothermic reactions are exothermic chemical reactions that are also using aluminium as the reducing agent at high temperature.
Even this process is industrially useful for production of alloys of iron.
For example: thermite reaction between iron oxides and aluminium to produce iron itself: Fe2O3 + 2 Al → 2 Fe + Al2O3