In the formation of Al₂O₃ huge amount of energy is released which makes it useful in

Thermite  welding is process in which fusion is produced by heating with superheated liquid metal and slag resulting from a chemical reaction between a metal oxide and aluminum, with or without the application of pressure. Filler metal, when used, is obtained from the liquid metal.The Thermite Process or Goldschmidt Process is the method of obtaining liquid metal by reduction of the oxide with aluminium powder, when ignited with magnesium ribbon it reacts by producing iron and aluminium oxide at an intensely high temperature approaching 3000 degrees Celsius.It was developed for making welding repairs in situ, such as rail tracks. It was adopted by the army for use in incendiary bombs.