Thermite-by: 2P3 Wang Zhi

  Thermite is a pyrotechnic composition of a metal powder and a metal oxide, which produces an exothermic oxidation-reduction reaction known as athermite reaction. If aluminum is the reducing agent it is called an aluminothermic reaction. Most varieties are not explosive, but can create short bursts of extremely high temperatures focused on a very small area for a short period of time.

 Iron (III) oxide

The aluminium reduces the oxide of another metal, most commonly iron oxide, because aluminium is highly reactive:

Fe₂O₃ + 2Al → 2Fe + Al₂O₃ + Heat

The products are aluminium oxide, free elemental iron, and a large amount of heat. The reactants are commonly powdered and mixed with a binder to keep the material solid and prevent separation.

The reaction is used for thermite welding, often used to join rail tracks. Other metal oxides can be used, such as chromium oxide, to generate elemental metal.Copper thermite, using copper oxide, is used for creating electric joints in a process called cadwelding:

3CuO + 2Al → 3Cu + Al₂O₃ + Heat

Some thermite-like mixtures are used as pyrotechnic initiators such as fireworks.

Thermites with nanosized particles are described through a variety of terms, such as metastable intermolecular composites, superthermite nanothermite, and nanocomposite energetic materials.

A mixture of thermite and sulfur produces thermate which lowers the melting point of the iron it contacts when reacting by forming a eutectic system. This is useful in cutting through steel.