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Thermite

Thermite (/ˈθɜːrmt/)[1] is a pyrotechnic composition of metal powder and metal oxide. When ignited by heat or chemical reaction, thermite undergoes an exothermic reduction-oxidation (redox) reaction. Most varieties are not explosive, but can create brief bursts of heat and high temperature in a small area. Its form of action is similar to that of other fuel-oxidizer mixtures, such as black powder.

A thermite mixture using iron (III) oxide

Thermites have diverse compositions. Fuels include aluminium, magnesium, titanium, zinc, silicon, and boron. Aluminium is common because of its high boiling point and low cost. Oxidizers include bismuth(III) oxide, boron(III) oxide, silicon(IV) oxide, chromium(III) oxide, manganese(IV) oxide, iron(III) oxide, iron(II,III) oxide, copper(II) oxide, and lead(II,IV) oxide.[2] In a thermochemical survey comprising twenty-five metals and thirty-two metal oxides, 288 out of 800 binary combinations were characterized by adiabatic temperatures greater than 2000 K.[3] Combinations like these, which possess the thermodynamic potential to produce very high temperatures, are either already known to be reactive or are plausible thermitic systems.

The reaction, also called the Goldschmidt process, is used for thermite welding, often used to join railway tracks. Thermites have also been used in metal refining, disabling munitions, and in incendiary weapons. Some thermite-like mixtures are used as pyrotechnic initiators in fireworks.

Chemical reactions edit

 
A thermite reaction using iron(III) oxide. The sparks flying outwards are globules of molten iron trailing smoke in their wake.

In the following example, elemental aluminium reduces the oxide of another metal, in this common example iron oxide, because aluminium forms stronger and more stable bonds with oxygen than iron:

Fe2O3 + 2 Al → 2 Fe + Al2O3

The products are aluminium oxide, elemental iron,[4] and a large amount of heat. The reactants are commonly powdered and mixed with a binder to keep the material solid and prevent separation.

Other metal oxides can be used, such as chromium oxide, to generate the given metal in its elemental form. For example, a copper thermite reaction using copper oxide and elemental aluminium can be used for creating electric joints in a process called cadwelding, that produces elemental copper (it may react violently):

3 CuO + 2 Al → 3 Cu + Al2O3

Thermites with nanosized particles are described by a variety of terms, such as metastable intermolecular composites, super-thermite,[5] nano-thermite,[6] and nanocomposite energetic materials.[7][8][9]

History edit

The thermite (thermit) reaction was discovered in 1893 and patented in 1895 by German chemist Hans Goldschmidt.[10][11] Consequently, the reaction is sometimes called the "Goldschmidt reaction" or "Goldschmidt process". Goldschmidt was originally interested in producing very pure metals by avoiding the use of carbon in smelting, but he soon discovered the value of thermite in welding.[12]

The first commercial application of thermite was the welding of tram tracks in Essen in 1899.[13]

Types edit

 
A thermite reaction taking place on a cast iron skillet

Red iron(III) oxide (Fe2O3, commonly known as rust) is the most common iron oxide used in thermite.[14][15][16] Black iron(II,III) oxide (Fe3O4, magnetite) also works.[17] Other oxides are occasionally used, such as MnO2 in manganese thermite, Cr2O3 in chromium thermite, SiO2 (quartz) in silicon thermite, or copper(II) oxide in copper thermite, but only for specialized purposes.[17] All of these examples use aluminium as the reactive metal. Fluoropolymers can be used in special formulations, Teflon with magnesium or aluminium being a relatively common example. Magnesium/Teflon/Viton is another pyrolant of this type.[18]

Combinations of dry ice (frozen carbon dioxide) and reducing agents such as magnesium, aluminium and boron follow the same chemical reaction as with traditional thermite mixtures, producing metal oxides and carbon. Despite the very low temperature of a dry ice thermite mixture, such a system is capable of being ignited with a flame.[19] When the ingredients are finely divided, confined in a pipe and armed like a traditional explosive, this cryo-thermite is detonatable and a portion of the carbon liberated in the reaction emerges in the form of diamond.[20]

In principle, any reactive metal could be used instead of aluminium. This is rarely done, because the properties of aluminium are nearly ideal for this reaction:

  • It forms a passivation layer making it safer to handle than many other reactive metals.[21]
  • Its relatively low melting point (660 °C) means that it is easy to melt the metal, so that the reaction can occur mainly in the liquid phase, thus it proceeds fairly quickly.
  • Its high boiling point (2519 °C) enables the reaction to reach very high temperatures, since several processes tend to limit the maximum temperature to just below the boiling point. Such a high boiling point is common among transition metals (e.g., iron and copper boil at 2887 and 2582 °C, respectively), but is especially unusual among the highly reactive metals (cf. magnesium and sodium, which boil at 1090 and 883 °C, respectively).
  • Further, the low density of the aluminium oxide formed as a result of the reaction tends to leave it floating on the resultant pure metal. This is particularly important for reducing contamination in a weld.

Although the reactants are stable at room temperature, they burn with an extremely intense exothermic reaction when they are heated to ignition temperature. The products emerge as liquids due to the high temperatures reached (up to 2500 °C (4532°F) with iron(III) oxide)—although the actual temperature reached depends on how quickly heat can escape to the surrounding environment. Thermite contains its own supply of oxygen and does not require any external source of air. Consequently, it cannot be smothered, and may ignite in any environment given sufficient initial heat. It burns well while wet, and cannot be easily extinguished with water—though enough water to remove sufficient heat may stop the reaction.[22] Small amounts of water boil before reaching the reaction. Even so, thermite is used for welding under water.[23]

The thermites are characterized by almost complete absence of gas production during burning, high reaction temperature, and production of molten slag. The fuel should have high heat of combustion and produce oxides with low melting point and high boiling point. The oxidizer should contain at least 25% oxygen, have high density, low heat of formation, and produce metal with low melting and high boiling points (so the energy released is not consumed in evaporation of reaction products). Organic binders can be added to the composition to improve its mechanical properties, but they tend to produce endothermic decomposition products, causing some loss of reaction heat and production of gases.[24]

The temperature achieved during the reaction determines the outcome. In an ideal case, the reaction produces a well-separated melt of metal and slag. For this, the temperature must be high enough to melt both reaction products, the resulting metal and the fuel oxide. Too low a temperature produces a mixture of sintered metal and slag; too high a temperature (above the boiling point of any reactant or product) leads to rapid production of gas, dispersing the burning reaction mixture, sometimes with effects similar to a low-yield explosion. In compositions intended for production of metal by aluminothermic reaction, these effects can be counteracted. Too low a reaction temperature (e.g., when producing silicon from sand) can be boosted with addition of a suitable oxidizer (e.g., sulfur in aluminium-sulfur-sand compositions); too high a temperature can be reduced by using a suitable coolant and/or slag flux. The flux often used in amateur compositions is calcium fluoride, as it reacts only minimally, has relatively low melting point, low melt viscosity at high temperatures (therefore increasing fluidity of the slag) and forms a eutectic with alumina. Too much flux, however, dilutes the reactants to the point of not being able to sustain combustion. The type of metal oxide also has dramatic influence to the amount of energy produced; the higher the oxide, the higher the amount of energy produced. A good example is the difference between manganese(IV) oxide and manganese(II) oxide, where the former produces too high temperature and the latter is barely able to sustain combustion; to achieve good results, a mixture with proper ratio of both oxides can be used.[25]

The reaction rate can be also tuned with particle sizes; coarser particles burn slower than finer particles. The effect is more pronounced with the particles requiring being heated to higher temperature to start reacting. This effect is pushed to the extreme with nano-thermites.

The temperature achieved in the reaction in adiabatic conditions, when no heat is lost to the environment, can be estimated using Hess's law – by calculating the energy produced by the reaction itself (subtracting the enthalpy of the reactants from the enthalpy of the products) and subtracting the energy consumed by heating the products (from their specific heat, when the materials only change their temperature, and their enthalpy of fusion and eventually enthalpy of vaporization, when the materials melt or boil). In real conditions, the reaction loses heat to the environment, the achieved temperature is therefore somewhat lower. The heat transfer rate is finite, so the faster the reaction is, the closer to adiabatic condition it runs and the higher is the achieved temperature.[26]

Iron thermite edit

The most common composition is iron thermite. The oxidizer used is usually either iron(III) oxide or iron(II,III) oxide. The former produces more heat. The latter is easier to ignite, likely due to the crystal structure of the oxide. Addition of copper or manganese oxides can significantly improve the ease of ignition. The density of prepared thermite is often as low as 0.7 g/cm3. This, in turn, results in relatively poor energy density (about 3 kJ/cm3), rapid burn times, and spray of molten iron due to the expansion of trapped air. Thermite can be pressed to densities as high as 4.9 g/cm3 (almost 16 kJ/cm3) with slow burning speeds (about 1 cm/s). Pressed thermite has higher melting power, i.e. it can melt a steel cup where a low-density thermite would fail.[27] Iron thermite with or without additives can be pressed into cutting devices that have heat-resistant casing and a nozzle.[28] Oxygen balanced iron thermite 2Al + Fe2O3 has theoretical maximum density of 4.175 g/cm3 an adiabatic burn temperature of 3135 K or 2862 °C or 5183 °F (with phase transitions included, limited by iron, which boils at 3135 K), the aluminium oxide is (briefly) molten and the produced iron is mostly liquid with part of it being in gaseous form - 78.4 g of iron vapor per kg of thermite are produced. The energy content is 945.4 cal/g (3 956 J/g). The energy density is 16,516 J/cm3.[29]

The original mixture, as invented, used iron oxide in the form of mill scale. The composition was very difficult to ignite.[24]

Copper thermite edit

Copper thermite can be prepared using either copper(I) oxide (Cu2O, red) or copper(II) oxide (CuO, black). The burn rate tends to be very fast and the melting point of copper is relatively low, so the reaction produces a significant amount of molten copper in a very short time. Copper(II) thermite reactions can be so fast that it can be considered a type of flash powder. An explosion can occur, which sends a spray of copper drops to considerable distances.[30] Oxygen-balanced mixture has theoretical maximum density of 5.109 g/cm3, adiabatic flame temperature 2843 K (phase transitions included) with the aluminium oxide being molten and copper in both liquid and gaseous form; 343 g of copper vapor per kg of this thermite are produced. The energy content is 974 cal/g.[29]

Copper(I) thermite has industrial uses in e.g., welding of thick copper conductors (cadwelding). This kind of welding is being evaluated also for cable splicing on the US Navy fleet, for use in high-current systems, e.g., electric propulsion.[31] Oxygen balanced mixture has theoretical maximum density of 5.280 g/cm3, adiabatic flame temperature 2843 K (phase transitions included) with the aluminium oxide being molten and copper in both liquid and gaseous form; 77.6 g of copper vapor per kg of this thermite are produced. The energy content is 575.5 cal/g.[29]

Thermates edit

Thermate composition is a thermite enriched with a salt-based oxidizer (usually nitrates, e.g., barium nitrate, or peroxides). In contrast with thermites, thermates burn with evolution of flame and gases. The presence of the oxidizer makes the mixture easier to ignite and improves penetration of target by the burning composition, as the evolved gas is projecting the molten slag and providing mechanical agitation.[24] This mechanism makes thermate more suitable than thermite for incendiary purposes and for emergency destruction of sensitive equipment (e.g., cryptographic devices), as thermite's effect is more localized.[citation needed]

Ignition edit

 
A thermite reaction using iron(III) oxide

Metals, under the right conditions, burn in a process similar to the combustion of wood or gasoline. In fact, rust is the result of oxidation of steel or iron at very slow rates. A thermite reaction results when the correct mixtures of metallic fuels combine and ignite. Ignition itself requires extremely high temperatures.[32]

Ignition of a thermite reaction normally requires a sparkler or easily obtainable magnesium ribbon, but may require persistent efforts, as ignition can be unreliable and unpredictable. These temperatures cannot be reached with conventional black powder fuses, nitrocellulose rods, detonators, pyrotechnic initiators, or other common igniting substances.[17] Even when the thermite is hot enough to glow bright red, it does not ignite, as it has a very high ignition temperature.[33] Starting the reaction is possible using a propane torch if done correctly.[34]

Often, strips of magnesium metal are used as fuses. Because metals burn without releasing cooling gases, they can potentially burn at extremely high temperatures. Reactive metals such as magnesium can easily reach temperatures sufficiently high for thermite ignition. Magnesium ignition remains popular among amateur thermite users, mainly because it can be easily obtained,[17] but a piece of the burning strip can fall off into the mixture, resulting in premature ignition.[citation needed]

The reaction between potassium permanganate and glycerol or ethylene glycol is used as an alternative to the magnesium method. When these two substances mix, a spontaneous reaction begins, slowly increasing the temperature of the mixture until it produces flames. The heat released by the oxidation of glycerine is sufficient to initiate a thermite reaction.[17]

Apart from magnesium ignition, some amateurs also choose to use sparklers to ignite the thermite mixture.[35] These reach the necessary temperatures and provide enough time before the burning point reaches the sample.[36] This can be a dangerous method, as the iron sparks, like the magnesium strips, burn at thousands of degrees and can ignite the thermite, though the sparkler itself is not in contact with it. This is especially dangerous with finely powdered thermite.[citation needed]

Match heads burn hot enough to ignite thermite. Use of match heads enveloped with aluminium foil and a sufficiently long viscofuse/electric match leading to the match heads is possible.[citation needed]

Similarly, finely powdered thermite can be ignited by a flint spark lighter, as the sparks are burning metal (in this case, the highly reactive rare-earth metals lanthanum and cerium).[37] Therefore, it is unsafe to strike a lighter close to thermite.[citation needed]

Civilian uses edit

 
Thermite reaction proceeding for a railway welding: Shortly after this, the liquid iron flows into the mould around the rail gap.
 
Remains of ceramic moulds for thermite welding like these, left by railway workers near Årstafältet tramway station in Stockholm, Sweden, can sometimes be found along tracks.

Thermite reactions have many uses. It is not an explosive; instead, it operates by exposing a very small area to extremely high temperatures. Intense heat focused on a small spot can be used to cut through metal or weld metal components together both by melting metal from the components, and by injecting molten metal from the thermite reaction itself.[citation needed]

Thermite may be used for repair by the welding in-place of thick steel sections such as locomotive axle-frames where the repair can take place without removing the part from its installed location.[38]

Thermite can be used for quickly cutting or welding steel such as rail tracks, without requiring complex or heavy equipment.[39][40] However, defects such as slag inclusions and voids (holes) are often present in such welded junctions, so great care is needed to operate the process successfully. The numerical analysis of thermite welding of rails has been approached similar to casting cooling analysis. Both this finite element analysis and experimental analysis of thermite rail welds has shown that weld gap is the most influential parameter affecting defect formation.[41] Increasing weld gap has been shown to reduce shrinkage cavity formation and cold lap welding defects, and increasing preheat and thermite temperature further reduces these defects. However, reducing these defects promotes a second form of defect: microporosity.[42] Care must also be taken to ensure that the rails remain straight, without resulting in dipped joints, which can cause wear on high speed and heavy axle load lines.[43]

A thermite reaction, when used to purify the ores of some metals, is called the thermite process, or aluminothermic reaction. An adaptation of the reaction, used to obtain pure uranium, was developed as part of the Manhattan Project at Ames Laboratory under the direction of Frank Spedding. It is sometimes called the Ames process.[44]

Copper thermite is used for welding together thick copper wires for the purpose of electrical connections. It is used extensively by the electrical utilities and telecommunications industries (exothermic welded connections).

Military uses edit

Thermite hand grenades and charges are typically used by armed forces in both an anti-materiel role and in the partial destruction of equipment, the latter being common when time is not available for safer or more thorough methods.[45][46] For example, thermite can be used for the emergency destruction of cryptographic equipment when there is a danger that it might be captured by enemy troops. Because standard iron-thermite is difficult to ignite, burns with practically no flame and has a small radius of action, standard thermite is rarely used on its own as an incendiary composition. In general, an increase in the volume of gaseous reaction products of a thermite blend increases the heat transfer rate (and therefore damage) of that particular thermite blend.[47] It is usually used with other ingredients that increase its incendiary effects. Thermate-TH3 is a mixture of thermite and pyrotechnic additives that have been found superior to standard thermite for incendiary purposes.[48] Its composition by weight is generally about 68.7% thermite, 29.0% barium nitrate, 2.0% sulfur, and 0.3% of a binder (such as PBAN).[48] The addition of barium nitrate to thermite increases its thermal effect, produces a larger flame, and significantly reduces the ignition temperature.[48] Although the primary purpose of Thermate-TH3 by the armed forces is as an incendiary anti-materiel weapon, it also has uses in welding together metal components.

A classic military use for thermite is disabling artillery pieces, and it has been used for this purpose since World War II, such as at Pointe du Hoc, Normandy.[49] Thermite can permanently disable artillery pieces without the use of explosive charges, so thermite can be used when silence is necessary to an operation. This can be done by inserting one or more armed thermite grenades into the breech, and then quickly closing it; this welds the breech shut and makes loading the weapon impossible.[50]

During World War II, both German and Allied incendiary bombs used thermite mixtures.[51][52] Incendiary bombs usually consisted of dozens of thin, thermite-filled canisters (bomblets) ignited by a magnesium fuse. Incendiary bombs created massive damage in many cities due to fires started by the thermite. Cities that primarily consisted of wooden buildings were especially susceptible. These incendiary bombs were used primarily during nighttime air raids. Bombsights could not be used at night, creating the need to use munitions that could destroy targets without the need for precision placement.

Hazards edit

 
The violent effects of thermite

Thermite usage is hazardous due to the extremely high temperatures produced and the extreme difficulty in smothering a reaction once initiated. Small streams of molten iron released in the reaction can travel considerable distances and may melt through metal containers, igniting their contents. Additionally, flammable metals with relatively low boiling points such as zinc (with a boiling point of 907 °C, which is about 1,370 °C below the temperature at which thermite burns) could potentially spray superheated boiling metal violently into the air if near a thermite reaction.[citation needed]

If, for some reason, thermite is contaminated with organics, hydrated oxides and other compounds able to produce gases upon heating or reaction with thermite components, the reaction products may be sprayed. Moreover, if the thermite mixture contains enough empty spaces with air and burns fast enough, the super-heated air also may cause the mixture to spray. For this reason it is preferable to use relatively crude powders, so the reaction rate is moderate and hot gases could escape the reaction zone.

Preheating of thermite before ignition can easily be done accidentally, for example by pouring a new pile of thermite over a hot, recently ignited pile of thermite slag. When ignited, preheated thermite can burn almost instantaneously, releasing light and heat energy at a much higher rate than normal and causing burns and eye damage at what would normally be a reasonably safe distance.[citation needed]

The thermite reaction can take place accidentally in industrial locations where workers use abrasive grinding and cutting wheels with ferrous metals. Using aluminium in this situation produces a mixture of oxides that can explode violently.[53]

Mixing water with thermite or pouring water onto burning thermite can cause a steam explosion, spraying hot fragments in all directions.[54]

Thermite's main ingredients were also utilized for their individual qualities, specifically reflectivity and heat insulation, in a paint coating or dope for the German zeppelin Hindenburg, possibly contributing to its fiery destruction. This was a theory put forward by the former NASA scientist Addison Bain, and later tested in small scale by the scientific reality-TV show MythBusters with semi-inconclusive results (it was proven not to be the fault of the thermite reaction alone, but instead conjectured to be a combination of that and the burning of hydrogen gas that filled the body of the Hindenburg).[55] The MythBusters program also tested the veracity of a video found on the Internet, whereby a quantity of thermite in a metal bucket was ignited while sitting on top of several blocks of ice, causing a sudden explosion. They were able to confirm the results, finding huge chunks of ice as far as 50 m from the point of explosion. Co-host Jamie Hyneman conjectured that this was due to the thermite mixture aerosolizing, perhaps in a cloud of steam, causing it to burn even faster. Hyneman also voiced skepticism about another theory explaining the phenomenon: that the reaction somehow separated the hydrogen and oxygen in the ice and then ignited them. This explanation claims that the explosion is due to the reaction of high temperature molten aluminium with water. Aluminium reacts violently with water or steam at high temperatures, releasing hydrogen and oxidizing in the process. The speed of that reaction and the ignition of the resulting hydrogen can easily account for the explosion verified.[56] This process is akin to the explosive reaction caused by dropping metallic potassium into water.

In popular culture edit

In the episode "A No-Rough-Stuff-Type Deal" of the crime drama television series Breaking Bad, Walter White uses thermite to burn through a security lock in order to steal a methylamine drum from a chemical plant.[57]

See also edit

  • ALICE (propellant) – rocket propellant
  • Thermal lance – Thermal tool that cuts dense heavy materials

References edit

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  47. ^ Collins, Eric S.; Pantoya, Michelle L.; Daniels, Michael A.; Prentice, Daniel J.; Steffler, Eric D.; D’Arche, Steven P. (15 March 2012). "Heat Flux Analysis of a Reacting Thermite Spray Impingent on a Substrate". Energy & Fuels. 26 (3): 1621–1628. doi:10.1021/ef201954d.
  48. ^ a b c US patent 5698812, Song, Eugene, "Thermite destructive device", issued 1997, assigned to United States Secretary of the Army 
  49. ^ . Pqasb.pqarchiver.com. 29 May 1994. Archived from the original on 24 July 2012. Retrieved 12 October 2011.
  50. ^ Boyle, Hal (26 July 1950). "Corporal Tells of Gunning of Yank Prisoners". Ellensburg Daily Record. Retrieved 28 July 2021.
  51. ^ Noderer, E R (30 August 1940). . Pqasb.pqarchiver.com. Archived from the original on 24 July 2012. Retrieved 12 October 2011.
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  53. ^ . Hanford.gov. 21 September 2001. Archived from the original on 25 November 2007. Retrieved 15 September 2009.
  54. ^ "Make Thermite with Iron Oxide and Aluminum". www.skylighter.com. Retrieved 27 January 2017.
  55. ^ Schwartz, John (21 November 2006). "The Best Science Show on Television?". The New York Times. Retrieved 11 October 2011.
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  57. ^ Hare, Jonathan (1 March 2012). "Breaking Bad III – thermite break-in". education in chemistry. Royal Society of Chemistry. Retrieved 16 August 2023.

Further reading edit

  • L. L. Wang, Z. A. Munir and Y. M. Maximov (1993). "Thermite reactions: their utilization in the synthesis and processing of materials". Journal of Materials Science. 28 (14): 3693–3708. Bibcode:1993JMatS..28.3693W. doi:10.1007/BF00353167. S2CID 96981164.
  • M. Beckert (2002). "Hans Goldschmidt and the aluminothermics". Schweissen und Schneiden. 54 (9): 522–526.

External links edit

thermite, confused, with, termite, thermate, thermalite, this, article, about, flammable, material, comic, book, character, comics, explosive, device, with, same, name, incendiary, grenade, ɜːr, pyrotechnic, composition, metal, powder, metal, oxide, when, igni. Not to be confused with termite thermate or Thermalite This article is about the flammable material For the comic book character see Thermite comics For the explosive device with the same name see incendiary grenade Thermite ˈ 8 ɜːr m aɪ t 1 is a pyrotechnic composition of metal powder and metal oxide When ignited by heat or chemical reaction thermite undergoes an exothermic reduction oxidation redox reaction Most varieties are not explosive but can create brief bursts of heat and high temperature in a small area Its form of action is similar to that of other fuel oxidizer mixtures such as black powder A thermite mixture using iron III oxideThermites have diverse compositions Fuels include aluminium magnesium titanium zinc silicon and boron Aluminium is common because of its high boiling point and low cost Oxidizers include bismuth III oxide boron III oxide silicon IV oxide chromium III oxide manganese IV oxide iron III oxide iron II III oxide copper II oxide and lead II IV oxide 2 In a thermochemical survey comprising twenty five metals and thirty two metal oxides 288 out of 800 binary combinations were characterized by adiabatic temperatures greater than 2000 K 3 Combinations like these which possess the thermodynamic potential to produce very high temperatures are either already known to be reactive or are plausible thermitic systems The reaction also called the Goldschmidt process is used for thermite welding often used to join railway tracks Thermites have also been used in metal refining disabling munitions and in incendiary weapons Some thermite like mixtures are used as pyrotechnic initiators in fireworks Contents 1 Chemical reactions 2 History 3 Types 3 1 Iron thermite 3 2 Copper thermite 3 3 Thermates 4 Ignition 5 Civilian uses 6 Military uses 7 Hazards 8 In popular culture 9 See also 10 References 11 Further reading 12 External linksChemical reactions edit nbsp A thermite reaction using iron III oxide The sparks flying outwards are globules of molten iron trailing smoke in their wake In the following example elemental aluminium reduces the oxide of another metal in this common example iron oxide because aluminium forms stronger and more stable bonds with oxygen than iron Fe2O3 2 Al 2 Fe Al2O3The products are aluminium oxide elemental iron 4 and a large amount of heat The reactants are commonly powdered and mixed with a binder to keep the material solid and prevent separation Other metal oxides can be used such as chromium oxide to generate the given metal in its elemental form For example a copper thermite reaction using copper oxide and elemental aluminium can be used for creating electric joints in a process called cadwelding that produces elemental copper it may react violently 3 CuO 2 Al 3 Cu Al2O3Thermites with nanosized particles are described by a variety of terms such as metastable intermolecular composites super thermite 5 nano thermite 6 and nanocomposite energetic materials 7 8 9 History editThe thermite thermit reaction was discovered in 1893 and patented in 1895 by German chemist Hans Goldschmidt 10 11 Consequently the reaction is sometimes called the Goldschmidt reaction or Goldschmidt process Goldschmidt was originally interested in producing very pure metals by avoiding the use of carbon in smelting but he soon discovered the value of thermite in welding 12 The first commercial application of thermite was the welding of tram tracks in Essen in 1899 13 Types edit nbsp A thermite reaction taking place on a cast iron skilletRed iron III oxide Fe2O3 commonly known as rust is the most common iron oxide used in thermite 14 15 16 Black iron II III oxide Fe3O4 magnetite also works 17 Other oxides are occasionally used such as MnO2 in manganese thermite Cr2O3 in chromium thermite SiO2 quartz in silicon thermite or copper II oxide in copper thermite but only for specialized purposes 17 All of these examples use aluminium as the reactive metal Fluoropolymers can be used in special formulations Teflon with magnesium or aluminium being a relatively common example Magnesium Teflon Viton is another pyrolant of this type 18 Combinations of dry ice frozen carbon dioxide and reducing agents such as magnesium aluminium and boron follow the same chemical reaction as with traditional thermite mixtures producing metal oxides and carbon Despite the very low temperature of a dry ice thermite mixture such a system is capable of being ignited with a flame 19 When the ingredients are finely divided confined in a pipe and armed like a traditional explosive this cryo thermite is detonatable and a portion of the carbon liberated in the reaction emerges in the form of diamond 20 In principle any reactive metal could be used instead of aluminium This is rarely done because the properties of aluminium are nearly ideal for this reaction It forms a passivation layer making it safer to handle than many other reactive metals 21 Its relatively low melting point 660 C means that it is easy to melt the metal so that the reaction can occur mainly in the liquid phase thus it proceeds fairly quickly Its high boiling point 2519 C enables the reaction to reach very high temperatures since several processes tend to limit the maximum temperature to just below the boiling point Such a high boiling point is common among transition metals e g iron and copper boil at 2887 and 2582 C respectively but is especially unusual among the highly reactive metals cf magnesium and sodium which boil at 1090 and 883 C respectively Further the low density of the aluminium oxide formed as a result of the reaction tends to leave it floating on the resultant pure metal This is particularly important for reducing contamination in a weld Although the reactants are stable at room temperature they burn with an extremely intense exothermic reaction when they are heated to ignition temperature The products emerge as liquids due to the high temperatures reached up to 2500 C 4532 F with iron III oxide although the actual temperature reached depends on how quickly heat can escape to the surrounding environment Thermite contains its own supply of oxygen and does not require any external source of air Consequently it cannot be smothered and may ignite in any environment given sufficient initial heat It burns well while wet and cannot be easily extinguished with water though enough water to remove sufficient heat may stop the reaction 22 Small amounts of water boil before reaching the reaction Even so thermite is used for welding under water 23 The thermites are characterized by almost complete absence of gas production during burning high reaction temperature and production of molten slag The fuel should have high heat of combustion and produce oxides with low melting point and high boiling point The oxidizer should contain at least 25 oxygen have high density low heat of formation and produce metal with low melting and high boiling points so the energy released is not consumed in evaporation of reaction products Organic binders can be added to the composition to improve its mechanical properties but they tend to produce endothermic decomposition products causing some loss of reaction heat and production of gases 24 The temperature achieved during the reaction determines the outcome In an ideal case the reaction produces a well separated melt of metal and slag For this the temperature must be high enough to melt both reaction products the resulting metal and the fuel oxide Too low a temperature produces a mixture of sintered metal and slag too high a temperature above the boiling point of any reactant or product leads to rapid production of gas dispersing the burning reaction mixture sometimes with effects similar to a low yield explosion In compositions intended for production of metal by aluminothermic reaction these effects can be counteracted Too low a reaction temperature e g when producing silicon from sand can be boosted with addition of a suitable oxidizer e g sulfur in aluminium sulfur sand compositions too high a temperature can be reduced by using a suitable coolant and or slag flux The flux often used in amateur compositions is calcium fluoride as it reacts only minimally has relatively low melting point low melt viscosity at high temperatures therefore increasing fluidity of the slag and forms a eutectic with alumina Too much flux however dilutes the reactants to the point of not being able to sustain combustion The type of metal oxide also has dramatic influence to the amount of energy produced the higher the oxide the higher the amount of energy produced A good example is the difference between manganese IV oxide and manganese II oxide where the former produces too high temperature and the latter is barely able to sustain combustion to achieve good results a mixture with proper ratio of both oxides can be used 25 The reaction rate can be also tuned with particle sizes coarser particles burn slower than finer particles The effect is more pronounced with the particles requiring being heated to higher temperature to start reacting This effect is pushed to the extreme with nano thermites The temperature achieved in the reaction in adiabatic conditions when no heat is lost to the environment can be estimated using Hess s law by calculating the energy produced by the reaction itself subtracting the enthalpy of the reactants from the enthalpy of the products and subtracting the energy consumed by heating the products from their specific heat when the materials only change their temperature and their enthalpy of fusion and eventually enthalpy of vaporization when the materials melt or boil In real conditions the reaction loses heat to the environment the achieved temperature is therefore somewhat lower The heat transfer rate is finite so the faster the reaction is the closer to adiabatic condition it runs and the higher is the achieved temperature 26 Iron thermite edit The most common composition is iron thermite The oxidizer used is usually either iron III oxide or iron II III oxide The former produces more heat The latter is easier to ignite likely due to the crystal structure of the oxide Addition of copper or manganese oxides can significantly improve the ease of ignition The density of prepared thermite is often as low as 0 7 g cm3 This in turn results in relatively poor energy density about 3 kJ cm3 rapid burn times and spray of molten iron due to the expansion of trapped air Thermite can be pressed to densities as high as 4 9 g cm3 almost 16 kJ cm3 with slow burning speeds about 1 cm s Pressed thermite has higher melting power i e it can melt a steel cup where a low density thermite would fail 27 Iron thermite with or without additives can be pressed into cutting devices that have heat resistant casing and a nozzle 28 Oxygen balanced iron thermite 2Al Fe2O3 has theoretical maximum density of 4 175 g cm3 an adiabatic burn temperature of 3135 K or 2862 C or 5183 F with phase transitions included limited by iron which boils at 3135 K the aluminium oxide is briefly molten and the produced iron is mostly liquid with part of it being in gaseous form 78 4 g of iron vapor per kg of thermite are produced The energy content is 945 4 cal g 3 956 J g The energy density is 16 516 J cm3 29 The original mixture as invented used iron oxide in the form of mill scale The composition was very difficult to ignite 24 Copper thermite edit Copper thermite can be prepared using either copper I oxide Cu2O red or copper II oxide CuO black The burn rate tends to be very fast and the melting point of copper is relatively low so the reaction produces a significant amount of molten copper in a very short time Copper II thermite reactions can be so fast that it can be considered a type of flash powder An explosion can occur which sends a spray of copper drops to considerable distances 30 Oxygen balanced mixture has theoretical maximum density of 5 109 g cm3 adiabatic flame temperature 2843 K phase transitions included with the aluminium oxide being molten and copper in both liquid and gaseous form 343 g of copper vapor per kg of this thermite are produced The energy content is 974 cal g 29 Copper I thermite has industrial uses in e g welding of thick copper conductors cadwelding This kind of welding is being evaluated also for cable splicing on the US Navy fleet for use in high current systems e g electric propulsion 31 Oxygen balanced mixture has theoretical maximum density of 5 280 g cm3 adiabatic flame temperature 2843 K phase transitions included with the aluminium oxide being molten and copper in both liquid and gaseous form 77 6 g of copper vapor per kg of this thermite are produced The energy content is 575 5 cal g 29 Thermates edit Main article Thermate Thermate composition is a thermite enriched with a salt based oxidizer usually nitrates e g barium nitrate or peroxides In contrast with thermites thermates burn with evolution of flame and gases The presence of the oxidizer makes the mixture easier to ignite and improves penetration of target by the burning composition as the evolved gas is projecting the molten slag and providing mechanical agitation 24 This mechanism makes thermate more suitable than thermite for incendiary purposes and for emergency destruction of sensitive equipment e g cryptographic devices as thermite s effect is more localized citation needed Ignition edit nbsp A thermite reaction using iron III oxide Metals under the right conditions burn in a process similar to the combustion of wood or gasoline In fact rust is the result of oxidation of steel or iron at very slow rates A thermite reaction results when the correct mixtures of metallic fuels combine and ignite Ignition itself requires extremely high temperatures 32 Ignition of a thermite reaction normally requires a sparkler or easily obtainable magnesium ribbon but may require persistent efforts as ignition can be unreliable and unpredictable These temperatures cannot be reached with conventional black powder fuses nitrocellulose rods detonators pyrotechnic initiators or other common igniting substances 17 Even when the thermite is hot enough to glow bright red it does not ignite as it has a very high ignition temperature 33 Starting the reaction is possible using a propane torch if done correctly 34 Often strips of magnesium metal are used as fuses Because metals burn without releasing cooling gases they can potentially burn at extremely high temperatures Reactive metals such as magnesium can easily reach temperatures sufficiently high for thermite ignition Magnesium ignition remains popular among amateur thermite users mainly because it can be easily obtained 17 but a piece of the burning strip can fall off into the mixture resulting in premature ignition citation needed The reaction between potassium permanganate and glycerol or ethylene glycol is used as an alternative to the magnesium method When these two substances mix a spontaneous reaction begins slowly increasing the temperature of the mixture until it produces flames The heat released by the oxidation of glycerine is sufficient to initiate a thermite reaction 17 Apart from magnesium ignition some amateurs also choose to use sparklers to ignite the thermite mixture 35 These reach the necessary temperatures and provide enough time before the burning point reaches the sample 36 This can be a dangerous method as the iron sparks like the magnesium strips burn at thousands of degrees and can ignite the thermite though the sparkler itself is not in contact with it This is especially dangerous with finely powdered thermite citation needed Match heads burn hot enough to ignite thermite Use of match heads enveloped with aluminium foil and a sufficiently long viscofuse electric match leading to the match heads is possible citation needed Similarly finely powdered thermite can be ignited by a flint spark lighter as the sparks are burning metal in this case the highly reactive rare earth metals lanthanum and cerium 37 Therefore it is unsafe to strike a lighter close to thermite citation needed Civilian uses edit nbsp Thermite reaction proceeding for a railway welding Shortly after this the liquid iron flows into the mould around the rail gap nbsp Remains of ceramic moulds for thermite welding like these left by railway workers near Arstafaltet tramway station in Stockholm Sweden can sometimes be found along tracks Thermite reactions have many uses It is not an explosive instead it operates by exposing a very small area to extremely high temperatures Intense heat focused on a small spot can be used to cut through metal or weld metal components together both by melting metal from the components and by injecting molten metal from the thermite reaction itself citation needed Thermite may be used for repair by the welding in place of thick steel sections such as locomotive axle frames where the repair can take place without removing the part from its installed location 38 Thermite can be used for quickly cutting or welding steel such as rail tracks without requiring complex or heavy equipment 39 40 However defects such as slag inclusions and voids holes are often present in such welded junctions so great care is needed to operate the process successfully The numerical analysis of thermite welding of rails has been approached similar to casting cooling analysis Both this finite element analysis and experimental analysis of thermite rail welds has shown that weld gap is the most influential parameter affecting defect formation 41 Increasing weld gap has been shown to reduce shrinkage cavity formation and cold lap welding defects and increasing preheat and thermite temperature further reduces these defects However reducing these defects promotes a second form of defect microporosity 42 Care must also be taken to ensure that the rails remain straight without resulting in dipped joints which can cause wear on high speed and heavy axle load lines 43 A thermite reaction when used to purify the ores of some metals is called the thermite process or aluminothermic reaction An adaptation of the reaction used to obtain pure uranium was developed as part of the Manhattan Project at Ames Laboratory under the direction of Frank Spedding It is sometimes called the Ames process 44 Copper thermite is used for welding together thick copper wires for the purpose of electrical connections It is used extensively by the electrical utilities and telecommunications industries exothermic welded connections Military uses editThermite hand grenades and charges are typically used by armed forces in both an anti materiel role and in the partial destruction of equipment the latter being common when time is not available for safer or more thorough methods 45 46 For example thermite can be used for the emergency destruction of cryptographic equipment when there is a danger that it might be captured by enemy troops Because standard iron thermite is difficult to ignite burns with practically no flame and has a small radius of action standard thermite is rarely used on its own as an incendiary composition In general an increase in the volume of gaseous reaction products of a thermite blend increases the heat transfer rate and therefore damage of that particular thermite blend 47 It is usually used with other ingredients that increase its incendiary effects Thermate TH3 is a mixture of thermite and pyrotechnic additives that have been found superior to standard thermite for incendiary purposes 48 Its composition by weight is generally about 68 7 thermite 29 0 barium nitrate 2 0 sulfur and 0 3 of a binder such as PBAN 48 The addition of barium nitrate to thermite increases its thermal effect produces a larger flame and significantly reduces the ignition temperature 48 Although the primary purpose of Thermate TH3 by the armed forces is as an incendiary anti materiel weapon it also has uses in welding together metal components A classic military use for thermite is disabling artillery pieces and it has been used for this purpose since World War II such as at Pointe du Hoc Normandy 49 Thermite can permanently disable artillery pieces without the use of explosive charges so thermite can be used when silence is necessary to an operation This can be done by inserting one or more armed thermite grenades into the breech and then quickly closing it this welds the breech shut and makes loading the weapon impossible 50 During World War II both German and Allied incendiary bombs used thermite mixtures 51 52 Incendiary bombs usually consisted of dozens of thin thermite filled canisters bomblets ignited by a magnesium fuse Incendiary bombs created massive damage in many cities due to fires started by the thermite Cities that primarily consisted of wooden buildings were especially susceptible These incendiary bombs were used primarily during nighttime air raids Bombsights could not be used at night creating the need to use munitions that could destroy targets without the need for precision placement Hazards edit nbsp The violent effects of thermiteThermite usage is hazardous due to the extremely high temperatures produced and the extreme difficulty in smothering a reaction once initiated Small streams of molten iron released in the reaction can travel considerable distances and may melt through metal containers igniting their contents Additionally flammable metals with relatively low boiling points such as zinc with a boiling point of 907 C which is about 1 370 C below the temperature at which thermite burns could potentially spray superheated boiling metal violently into the air if near a thermite reaction citation needed If for some reason thermite is contaminated with organics hydrated oxides and other compounds able to produce gases upon heating or reaction with thermite components the reaction products may be sprayed Moreover if the thermite mixture contains enough empty spaces with air and burns fast enough the super heated air also may cause the mixture to spray For this reason it is preferable to use relatively crude powders so the reaction rate is moderate and hot gases could escape the reaction zone Preheating of thermite before ignition can easily be done accidentally for example by pouring a new pile of thermite over a hot recently ignited pile of thermite slag When ignited preheated thermite can burn almost instantaneously releasing light and heat energy at a much higher rate than normal and causing burns and eye damage at what would normally be a reasonably safe distance citation needed The thermite reaction can take place accidentally in industrial locations where workers use abrasive grinding and cutting wheels with ferrous metals Using aluminium in this situation produces a mixture of oxides that can explode violently 53 Mixing water with thermite or pouring water onto burning thermite can cause a steam explosion spraying hot fragments in all directions 54 Thermite s main ingredients were also utilized for their individual qualities specifically reflectivity and heat insulation in a paint coating or dope for the German zeppelin Hindenburg possibly contributing to its fiery destruction This was a theory put forward by the former NASA scientist Addison Bain and later tested in small scale by the scientific reality TV show MythBusters with semi inconclusive results it was proven not to be the fault of the thermite reaction alone but instead conjectured to be a combination of that and the burning of hydrogen gas that filled the body of the Hindenburg 55 The MythBusters program also tested the veracity of a video found on the Internet whereby a quantity of thermite in a metal bucket was ignited while sitting on top of several blocks of ice causing a sudden explosion They were able to confirm the results finding huge chunks of ice as far as 50 m from the point of explosion Co host Jamie Hyneman conjectured that this was due to the thermite mixture aerosolizing perhaps in a cloud of steam causing it to burn even faster Hyneman also voiced skepticism about another theory explaining the phenomenon that the reaction somehow separated the hydrogen and oxygen in the ice and then ignited them This explanation claims that the explosion is due to the reaction of high temperature molten aluminium with water Aluminium reacts violently with water or steam at high temperatures releasing hydrogen and oxidizing in the process The speed of that reaction and the ignition of the resulting hydrogen can easily account for the explosion verified 56 This process is akin to the explosive reaction caused by dropping metallic potassium into water In popular culture editIn the episode A No Rough Stuff Type Deal of the crime drama television series Breaking Bad Walter White uses thermite to burn through a security lock in order to steal a methylamine drum from a chemical plant 57 See also editALICE propellant rocket propellantPages displaying wikidata descriptions as a fallback Thermal lance Thermal tool that cuts dense heavy materialsReferences edit Wells John C 1990 Longman pronunciation dictionary Harlow England Longman p 715 ISBN 978 0 582 05383 0 entry thermite Kosanke K Kosanke B J Von Maltitz I Sturman B Shimizu T Wilson M A Kubota N Jennings White C Chapman D December 2004 Pyrotechnic Chemistry Google Books Journal of Pyrotechnics Incorporated ISBN 978 1 889526 15 7 Retrieved 15 September 2009 Shaw Anthony Peter Gordon 5 June 2020 Thermitic Thermodynamics A Computational Survey and Comprehensive Interpretation of Over 800 Combinations of Metals Metalloids and Oxides Boca Raton CRC Press p 33 doi 10 1201 9781351056625 ISBN 978 1 351 05662 5 Demo Lab The Thermite Reaction Ilpi com Retrieved 11 October 2011 Low Cost Production of Nanostructured Super Thermites Navysbir com Retrieved 12 October 2011 Foley Timothy Pacheco Adam Malchi Jonathan Yetter Richard Higa Kelvin 2007 Development of Nanothermite Composites with Variable Electrostatic Discharge Ignition Thresholds Propellants Explosives Pyrotechnics 32 6 431 doi 10 1002 prep 200700273 OSTI 1454970 Reaction Kinetics and Thermodynamics of Nanothermite Propellants Ci confex com Archived from the original on 13 August 2011 Retrieved 15 September 2009 Dreizin E L Schoenitz M 2017 Mechanochemically prepared reactive and energetic materials a review Journal of Materials Science 52 20 11789 11809 Bibcode 2017JMatS 5211789D doi 10 1007 s10853 017 0912 1 S2CID 136215486 Apperson S Shende R V Subramanian S Tappmeyer D Gangopadhyay S Chen Z Gangopadhyay K Redner P et al 2007 Generation of fast propagating combustion and shock waves with copper oxide aluminum nanothermite composites PDF Applied Physics Letters 91 24 243109 Bibcode 2007ApPhL 91x3109A doi 10 1063 1 2787972 hdl 10355 8197 Goldschmidt H 13 March 1895 Verfahren zur Herstellung von Metallen oder Metalloiden oder Legierungen derselben Process for the production of metals or metalloids or alloys of the same Deutsche Reichs Patent no 96317 Thermit Encyclopedia Britannica www britannica com 30 March 2011 Retrieved 14 August 2022 Goldschmidt Hans Vautin Claude 30 June 1898 Aluminium as a Heating and Reducing Agent PDF Journal of the Society of Chemical Industry 6 17 543 545 Archived from the original PDF on 15 July 2011 Retrieved 12 October 2011 Goldschmidt Thermit Group Goldschmidt thermit com Archived from the original on 5 April 2012 Retrieved 12 October 2011 Thermite Bombs used to Set Fires The Milwaukee Journal 1 December 1939 Retrieved 13 October 2011 permanent dead link dead link 25 April 2020 what it Means Thermite Bombing the Florence Times 31 August 1940 Retrieved 12 October 2011 Hydrogen May Not Have Caused Hindenburg s Fiery End The New York Times 6 May 1997 Retrieved 12 October 2011 a b c d e Thermite Amazing Rust com 7 February 2001 Archived from the original on 7 July 2011 Retrieved 12 October 2011 Koch Ernst Christian 2002 Metal Fluorocarbon Pyrolants III Development and Application of Magnesium Teflon Viton MTV Propellants Explosives Pyrotechnics 27 5 262 266 doi 10 1002 1521 4087 200211 27 5 lt 262 AID PREP262 gt 3 0 CO 2 8 Burning magnesium in dry ice Royal Society of Chemistry Archived from the original on 11 December 2021 via YouTube Swanson Daren 21 December 2007 Method For Creating Diamonds www EnviroDiamond com Daren Swanson Granier J J Plantier K B Pantoya M L 2004 The role of the Al2O3 passivation shell surrounding nano Al particles in the combustion synthesis of NiAl Journal of Materials Science 39 21 6421 Bibcode 2004JMatS 39 6421G doi 10 1023 B JMSC 0000044879 63364 b3 S2CID 137141668 Wohletz Kenneth 2002 Water magma interaction some theory and experiments on peperite formation Journal of Volcanology and Geothermal Research 114 1 2 19 35 Bibcode 2002JVGR 114 19W doi 10 1016 S0377 0273 01 00280 3 Sarah Lyall 27 October 2006 Cameras Catch Speeding Britons and Lots of Grief The New York Times Retrieved 12 October 2011 a b c K Kosanke B J Kosanke I von Maltitz B Sturman T Shimizu M A Wilson N Kubota C Jennings White D Chapman December 2004 Pyrotechnic Chemistry Journal of Pyrotechnics pp 126 ISBN 978 1 889526 15 7 Retrieved 9 January 2012 Manganese thermite based on manganese II oxide Developing your Web presence 10 July 2008 Retrieved 7 December 2011 Gupta Chiranjib Kumar 2006 Chemical Metallurgy Principles and Practice John Wiley amp Sons pp 387 ISBN 978 3 527 60525 5 Elshenawy Tamer Soliman Salah Hawass Ahmed October 2017 High density thermite mixture for shaped charge ordnance disposal Defence Technology 13 5 376 379 doi 10 1016 j dt 2017 03 005 TEC Torch Energetic Materials amp Products Inc Central Texas a b c Fischer S H Grubelich M C August 1996 A survey of combustible metals thermites and intermetallics for pyrotechnic applications 32 AIAA ASME SAE ASEE joint propulsion conference and exhibit Thermite PyroGuide 3 March 2011 Archived from the original on 6 April 2012 Retrieved 6 December 2011 HTS gt News Item Hts asminternational org 1 August 2011 Retrieved 6 December 2011 Kosanke K L Sturman Barry T Winokur Robert M Kosanke B J 2012 Encyclopedic Dictionary of Pyrotechnics and Related Subjects Journal of Pyrotechnics p 1114 ISBN 978 1 889526 21 8 Helmenstine Anne Marie 8 December 2019 How to Safely Perform a Thermite Reaction ThoughtCo Archived from the original on 8 January 2023 Retrieved 24 February 2023 Nakka Richard 2 May 2007 Richard Nakka s Experimental Rocketry Site Nakka rocketry net Retrieved 12 October 2011 Hardaker David 23 September 2004 The World Today Virgin Blue security scare Abc net au Archived from the original on 15 January 2005 Retrieved 12 October 2011 Gray Theodore 19 August 2004 Making Steel with Beach Sand Popular Science Popsci com Archived from the original on 8 September 2012 Retrieved 12 October 2011 Shurlite 21 September 2010 Material Safety Data Sheet Lighter Flints Ferro Cerrium PDF shurlite com Archived from the original PDF on 24 August 2015 Retrieved 22 January 2012 Jeffus Larry 2012 Welding principles and applications 7th ed Clifton Park N Y Delmar Cengage Learning p 744 ISBN 978 1111039172 Papers Past Star 15 November 1906 NEW WELDING PROCESS Paperspast natlib govt nz 15 November 1906 Retrieved 12 October 2011 How Many Ways to Weld Metal Eugene Register Guard 8 December 1987 Retrieved 12 October 2011 Chen Y Lawrence F V Barkan C P L Dantzig J A 24 October 2006 Heat transfer modelling of rail thermite welding Proceedings of the Institution of Mechanical Engineers Part F Journal of Rail and Rapid Transit 220 3 207 217 CiteSeerX 10 1 1 540 9423 doi 10 1243 09544097F01505 S2CID 17438646 Chen Y Lawrence F V Barkan C P L Dantzig J A 14 December 2006 Weld defect formation in rail thermite welds Proceedings of the Institution of Mechanical Engineers Part F Journal of Rail and Rapid Transit 220 4 373 384 CiteSeerX 10 1 1 501 2867 doi 10 1243 0954409JRRT44 S2CID 16624977 Strengthening the track structure for heavy axle loads strengthening track infrastructure provides another method of dealing with ever increasing car capacities TTCI R amp D Goliath Business News 1 September 2002 Retrieved 12 October 2011 US patent 2830894 Spedding Frank H Wilhelm Harley A amp Keller Wayne H Production of Uranium issued 1958 assigned to United States Atomic Energy Commission Grenades and Pyrotechnics Signals Field Manual No 23 30 PDF Department of the Army 27 December 1988 Archived from the original on 19 January 2012 a href Template Cite web html title Template Cite web cite web a CS1 maint unfit URL link AN M14 TH3 incendiary hand grenade Military Analysis Network Federation of American Scientists Retrieved 2 October 2023 Collins Eric S Pantoya Michelle L Daniels Michael A Prentice Daniel J Steffler Eric D D Arche Steven P 15 March 2012 Heat Flux Analysis of a Reacting Thermite Spray Impingent on a Substrate Energy amp Fuels 26 3 1621 1628 doi 10 1021 ef201954d a b c US patent 5698812 Song Eugene Thermite destructive device issued 1997 assigned to United States Secretary of the Army THE INVASION CHAPTER 9 THE GUNS OF POINTE DU HOC Pqasb pqarchiver com 29 May 1994 Archived from the original on 24 July 2012 Retrieved 12 October 2011 Boyle Hal 26 July 1950 Corporal Tells of Gunning of Yank Prisoners Ellensburg Daily Record Retrieved 28 July 2021 Noderer E R 30 August 1940 Archives Chicago Tribune Pqasb pqarchiver com Archived from the original on 24 July 2012 Retrieved 12 October 2011 Bitter Fighting in Libya The Indian Express 25 November 1941 Retrieved 12 October 2011 Fireball from Aluminum and Grinding Dust Hanford gov 21 September 2001 Archived from the original on 25 November 2007 Retrieved 15 September 2009 Make Thermite with Iron Oxide and Aluminum www skylighter com Retrieved 27 January 2017 Schwartz John 21 November 2006 The Best Science Show on Television The New York Times Retrieved 11 October 2011 Molten Metal Explosions PDF Modern Media Communications Ltd Retrieved 15 March 2012 permanent dead link Hare Jonathan 1 March 2012 Breaking Bad III thermite break in education in chemistry Royal Society of Chemistry Retrieved 16 August 2023 Further reading editL L Wang Z A Munir and Y M Maximov 1993 Thermite reactions their utilization in the synthesis and processing of materials Journal of Materials Science 28 14 3693 3708 Bibcode 1993JMatS 28 3693W doi 10 1007 BF00353167 S2CID 96981164 M Beckert 2002 Hans Goldschmidt and the aluminothermics Schweissen und Schneiden 54 9 522 526 External links edit nbsp Look up thermite in Wiktionary the free dictionary Thermite Pictures amp Videos Including Exotic Thermite Archived 24 March 2010 at the Wayback Machine Video steel casting with thermite Goldschmidt Process Encyclopedia Americana 1920 Retrieved from https en wikipedia org w index php title Thermite amp oldid 1206883803, wikipedia, wiki, book, books, library,

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