What is a thermit reaction? State one use of this reaction

What is a thermit reaction? State one use of this reaction.
Answer:
The reaction between iron(III) oxide (Fe203) and aluminium gives out lots of heat.
It is called the thermit reaction.
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This displacement reaction is used to join railway tracks or cracked machine parts.
The heat given out in the reaction melts the iron formed. The molten iron runs down between the tracks and welds them together.