Chemical Reactions
The aluminium reduces the oxide of another metal, most commonly iron oxide, because aluminium is more reactive:
- Fe2O3 + 2 Al → 2 Fe + Al2O3
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 the given metal in its elemental form. Copper thermite, using copper oxide, is used for creating electric joints in a process called cadwelding:
- 3 CuO + 2 Al → 3 Cu + Al2O3
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, super-thermite, nano-thermite, and nanocomposite energetic materials.
Read more about this topic: Thermite
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