Thermite: Difference between revisions
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The basic mixture in a thermite is a powdered metal, most often [[aluminum powder]], and a metal oxide, most often [[ferric oxide]]. | The basic mixture in a thermite is a powdered metal, most often [[aluminum powder]], and a metal oxide, most often [[ferric oxide]]. | ||
==Civilian applications== | ==Civilian applications== | ||
Thermites and thermates are used in specialized welding and metal-cutting applications. The reacting mixture, and the molten metal it produces, often needs to be contained by ceramics, or it may cut away its own support and fall away from the work. It normally, therefore, needs to react on a horizontal surface. This requirement does throw doubt on some conspiracy theories associated with the [[9-11 | Thermites and thermates are used in specialized welding and metal-cutting applications. The reacting mixture, and the molten metal it produces, often needs to be contained by ceramics, or it may cut away its own support and fall away from the work. It normally, therefore, needs to react on a horizontal surface. This requirement does throw doubt on some conspiracy theories associated with the [[9-11 attack in New York]], which suggest that preplanted thermite was used to cut vertical supports in the World Trade Center. | ||
One application, which lends itself to the horizontal placement, is welding railroad rails. A relatively small amount of thermite can replace cumbersome gas welding tanks or the need for electric power for arc welding. This type of welding is used as a spectacular demonstration in high school chemistry, although it generally is too dangerous for inexperienced students to perform.<ref>{{citation | |||
| title = (Abstract) Report: Thermite Welding Gets High School Chemistry Class on Track | |||
| author = Anthony L. Feliu | |||
| journal = J. Chem. Educ. | year = 2001 | volume= 78 | issue = 1 | page = 15 | |||
| doi= 10.1021/ed078p15 | |||
| date = 1 January 2001 | url = http://pubs.acs.org/doi/abs/10.1021/ed078p15 | |||
}}</ref> | |||
==Military applications== | ==Military applications== | ||
It was first used as a military incendiary in the [[First World War]], dropped from German [[zeppelin]]s. The German formulation was of [[magnesium]] powder and [[magnesium oxide]]; the French introduced the aluminum-iron oxide. Allied troops also introduced destruction grenades that raiding units used to destroy German equipment. | It was first used as a military incendiary in the [[First World War]], dropped from German [[zeppelin]]s. The German formulation was of [[magnesium]] powder and [[magnesium oxide]]; the French introduced the aluminum-iron oxide. Allied troops also introduced destruction grenades that raiding units used to destroy German equipment. | ||
Revision as of 20:28, 11 March 2011
Rather than being a specific formula, as is often misunderstood, thermite is a class of chemical mixtures that, when ignited by a sufficiently hot source, react to give extremely high temperatures. Thermites and variants on them have a variety of civilian and military applications, from specialized welding, to incendiary formulations, to destruction charges used to make equipment useless if captured.
The basic mixture in a thermite is a powdered metal, most often aluminum powder, and a metal oxide, most often ferric oxide.
Civilian applications
Thermites and thermates are used in specialized welding and metal-cutting applications. The reacting mixture, and the molten metal it produces, often needs to be contained by ceramics, or it may cut away its own support and fall away from the work. It normally, therefore, needs to react on a horizontal surface. This requirement does throw doubt on some conspiracy theories associated with the 9-11 attack in New York, which suggest that preplanted thermite was used to cut vertical supports in the World Trade Center.
One application, which lends itself to the horizontal placement, is welding railroad rails. A relatively small amount of thermite can replace cumbersome gas welding tanks or the need for electric power for arc welding. This type of welding is used as a spectacular demonstration in high school chemistry, although it generally is too dangerous for inexperienced students to perform.[1]
Military applications
It was first used as a military incendiary in the First World War, dropped from German zeppelins. The German formulation was of magnesium powder and magnesium oxide; the French introduced the aluminum-iron oxide. Allied troops also introduced destruction grenades that raiding units used to destroy German equipment.
Great use was made of the thermate variant as an air-dropped incendiary in the Second World War.[2]
References
- ↑ Anthony L. Feliu (1 January 2001), "(Abstract) Report: Thermite Welding Gets High School Chemistry Class on Track", J. Chem. Educ. 78 (1): 15, DOI:10.1021/ed078p15
- ↑ Military Explosives, U.S. Department of the Army, September 1984, TM 9-1300-214, pp. 2-10 to 2-12