thermite

Thermite is a pyrotechnic composition used for producing very high temperatures through an aluminothermic reaction. It typically consists of a metal oxide, commonly iron(III) oxide, and aluminum powder. When ignited, the aluminum reduces the metal oxide to metal while forming aluminum oxide, releasing a large amount of heat. The classical reaction is 2 Al + Fe2O3 → 2 Fe + Al2O3, which can reach temperatures up to about 2500–3000 °C at the reaction site.

Thermite is used primarily in metallurgy and construction for joining or cutting metal. Thermite welding, also known as aluminothermic welding, is a process used to weld rails and heavy sections by melting a large amount of iron with molten slag that fuses parts together. Other oxide combinations produce different reactive metals and are used in research and specialized industrial processes. Variants include copper oxide or chromium oxide thermites, among others, typically designed for specific metallurgical outcomes.

Safety and handling are essential. The reaction is extremely exothermic and produces molten metal and slag that can cause severe burns, fires, and property damage. It is not explosive, but should be performed only by trained personnel with appropriate containment and protective equipment. Thermite technology dates to the late 19th century, developed by Hans Goldschmidt, and has since found diverse applications in industry and, in some cases, military contexts.