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A pyrotechnic composition is a substance or mixture of substances designed to produce an effect by heat, light, sound, gas/smoke or a combination of these, as a result of non-detonative self-sustaining
exothermic In thermodynamics, an exothermic process () is a thermodynamic process or reaction that releases energy from the system to its surroundings, usually in the form of heat, but also in a form of light (e.g. a spark, flame, or flash), electricity ...
chemical reactions. Pyrotechnic substances do not rely on oxygen from external sources to sustain the reaction.


Types

Basic types of pyrotechnic compositions are: * flash powder – burns very fast, produces explosions and/or bright flashes of light *
gunpowder Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, carbon (in the form of charcoal) and potassium nitrate (saltpeter). T ...
– burns slower than flash powder, produces large amount of gases * solid
propellant A propellant (or propellent) is a mass that is expelled or expanded in such a way as to create a thrust or other motive force in accordance with Newton's third law of motion, and "propel" a vehicle, projectile, or fluid payload. In vehicles, the ...
s – produce large amount of hot gases, used as sources of kinetic energy for rockets and projectiles *
pyrotechnic initiator In pyrotechnics, a pyrotechnic initiator (also initiator or igniter) is a device containing a pyrotechnic composition used primarily to ignite other, more difficult-to-ignite materials, such as thermites, gas generators, and solid-fuel rockets. The ...
s – produce large amount of heat, flames, and/or hot sparks, used to ignite other compositions *
gas generator A gas generator is a device for generating gas. A gas generator may create gas by a chemical reaction or from a solid or liquid source, when storing a pressurized gas is undesirable or impractical. The term often refers to a device that uses a ...
s – produce large amount of gas, either high volume at short time (for actuators and ejection charges, often using solid propellants) or controlled flow rate (e.g.
chemical oxygen generator A chemical oxygen generator is a device that releases oxygen via a chemical reaction. The oxygen source is usually an inorganic superoxide, chlorate, or perchlorate; ozonides are a promising group of oxygen sources. The generators are usually ig ...
s, often using thermite-like compositions) * ejection charges – burn fast, produce large amount of gas at short time, used to eject payloads from containers * burst charges – burn fast, produce large amount of gas at short time, used to fragment a container and eject its content *
smoke composition A smoke composition is a pyrotechnic composition designed primarily to generate smoke. Smoke compositions are used as obscurants or for generation of signaling smokes. Some are used as a payload of smoke bombs and smoke grenades. Obscurants Smok ...
s – burn slowly, produce smoke, plain or colored * delay compositions – burn at constant slow speed, used to introduce delays into the firing train *
pyrotechnic heat source A pyrotechnic heat source, also called heat pellet, is a pyrotechnic device based on a pyrotechnic composition with a suitable igniter. Its role is to produce controlled amount of heat. Pyrotechnic heat sources are usually based on thermite-like ( ...
s – produce large amount of heat and little to no gases, slow-burning, often thermite-like compositions * sparklers – producing white or colored sparks * flares – burn slowly, produce high amount of light, used for illumination or signaling * coloured
fireworks Fireworks are a class of low explosive pyrotechnic devices used for aesthetic and entertainment purposes. They are most commonly used in fireworks displays (also called a fireworks show or pyrotechnics), combining a large number of devices ...
compositions – produce light, white or colored Some pyrotechnic compositions are used in industry and
aerospace Aerospace is a term used to collectively refer to the atmosphere and outer space. Aerospace activity is very diverse, with a multitude of commercial, industrial and military applications. Aerospace engineering consists of aeronautics and ast ...
for generation of large volumes of gas in
gas generator A gas generator is a device for generating gas. A gas generator may create gas by a chemical reaction or from a solid or liquid source, when storing a pressurized gas is undesirable or impractical. The term often refers to a device that uses a ...
s (e.g. in
airbag An airbag is a vehicle occupant-restraint system using a bag designed to inflate extremely quickly, then quickly deflate during a collision. It consists of the airbag cushion, a flexible fabric bag, an inflation module, and an impact sensor. T ...
s), in pyrotechnic fasteners, and in other similar applications. They are also used in military pyrotechnics, when production of large amount of noise, light, or infrared radiation is required; e.g. missile decoy flares, flash powders, and stun grenades. A new class of reactive material compositions is now under investigation by military. Many pyrotechnic compositions – especially involving aluminium and perchlorates – are often highly sensitive to friction, impact, and
static electricity Static electricity is an imbalance of electric charges within or on the surface of a material or between materials. The charge remains until it is able to move away by means of an electric current or electrical discharge. Static electricity is na ...
. Even as little as 0.1–10 millijoules spark can set off certain mixtures.


Materials used

Pyrotechnic compositions are usually homogenized mixtures of small particles of fuels and oxidizers. The particles can be grains or flakes. Generally, the higher the surface area of the particles, the higher the reaction rate and burning speed. For some purposes, binders are used to turn the powder into a solid material.


Fuels

Typical fuels are based on metal or
metalloid A metalloid is a type of chemical element which has a preponderance of properties in between, or that are a mixture of, those of metals and nonmetals. There is no standard definition of a metalloid and no complete agreement on which elements are ...
powders. A flash powder composition may specify multiple different fuels. Some fuels can also serve as binders. Common fuels include: *
Metal A metal (from ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electrical resistivity and conductivity, e ...
s **
Aluminium Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It ha ...
– most common fuel in many classes of mixtures, also a combustion instability suppressant. Less energy per mass than carbon but less gas evolution, retaining heat in the reaction mixture. High-temperature flame with solid particles, which interfere with flame colorants. Reacts with nitrates, except ammonium nitrate, yielding nitrogen oxides, ammonia, and heat (the reaction is slow at room temperature but violent at above 80 °C and may spontaneously ignite); the reaction can be inhibited by a weak acid, e.g. boric acid. Corroded by alkaline substances. Flake particles easier to ignite and better for pyrotechnics than spherical ones. In presence of moisture reacts with potassium chlorate and perchlorate, yielding hydrogen. Particle size selected according to the required burn rate. **
Magnesium Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ...
– more sensitive and violent than aluminium, increases probability of spontaneous ignition in storage. Used in fireworks to increase flame temperature. Less interference with flame color than aluminium. ** Magnalium – aluminium-magnesium alloy, more stable and less expensive than magnesium; less reactive than magnesium, easier to ignite than aluminium **
Iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in ...
– makes gold sparks, frequently used **
Steel Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistan ...
– an alloy of iron and carbon, makes branching yellow-orange sparks **
Zirconium Zirconium is a chemical element with the symbol Zr and atomic number 40. The name ''zirconium'' is taken from the name of the mineral zircon, the most important source of zirconium. The word is related to Persian '' zargun'' (zircon; ''zar-gun'' ...
– produces hot particles, good for ignition mixtures, e.g. the '' NASA Standard Initiator'', also a combustion instability suppressant **
Titanium Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion i ...
– produces hot particles, increases sensitivity to impact and friction; sometimes the Ti4Al6V alloy is used which gives a bit brighter white sparks; together with potassium perchlorate it is used in some
pyrotechnic igniter In pyrotechnics, a pyrotechnic initiator (also initiator or igniter) is a device containing a pyrotechnic composition used primarily to ignite other, more difficult-to-ignite materials, such as thermites, gas generators, and solid-fuel rockets. T ...
s; coarse powder produces beautiful branching blue-white sparks ** Ferrotitanium – iron-titanium alloy, produces bright yellow-white sparks, used in pyrotechnic stars, rockets, comets, and fountains ** Ferrosilicon – iron-silicon alloy, used in some mixtures, sometimes replacement of calcium silicide **
Manganese Manganese is a chemical element with the Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of ...
– used to control burn rates, e.g. in delay compositions **
Zinc Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...
– used in some
smoke composition A smoke composition is a pyrotechnic composition designed primarily to generate smoke. Smoke compositions are used as obscurants or for generation of signaling smokes. Some are used as a payload of smoke bombs and smoke grenades. Obscurants Smok ...
s, together with sulfur used in some early amateur rocket fuels, also in pyrotechnic stars; heavy, zinc-based compositions may require additional lift to fly high enough; moisture-sensitive; can spontaneously ignite; rarely used as primary fuel except in smoke compositions, can be encountered as a secondary enhancement fuel **
Copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pink ...
– used as a blue colorant with other fuels **
Brass Brass is an alloy of copper (Cu) and zinc (Zn), in proportions which can be varied to achieve different mechanical, electrical, and chemical properties. It is a substitutional alloy: atoms of the two constituents may replace each other wi ...
– a zinc-copper alloy used in some fireworks formulas, as a blue colorant for its copper content **
Tungsten Tungsten, or wolfram, is a chemical element with the symbol W and atomic number 74. Tungsten is a rare metal found naturally on Earth almost exclusively as compounds with other elements. It was identified as a new element in 1781 and first isol ...
– used to control and slow down burn rates of compositions, also in delay compositions ** Zirconium-
nickel Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow t ...
alloy – used in some military delay compositions * Metal hydrides (lower
heat of combustion The heating value (or energy value or calorific value) of a substance, usually a fuel or food (see food energy), is the amount of heat released during the combustion of a specified amount of it. The ''calorific value'' is the total energy rele ...
than pure metals, but increased sensitivity/reactivity to water): **
Titanium(II) hydride Titanium hydride normally refers to the inorganic compound and related nonstoichiometric materials. It is commercially available as a stable grey/black powder, which is used as an additive in the production of Alnico sintered magnets, in the sin ...
– together with potassium perchlorate it is used in some igniters ** Zirconium(II) hydride – together with potassium perchlorate it is used in some igniters ** Aluminum hydride – unstable for storage (decomposes easily with humidity) and reacts dangerously in contact with water **
Decaborane Decaborane, also called decaborane(14), is the borane with the chemical formula B10 H14. This white crystalline compound is one of the principal boron hydride clusters, both as a reference structure and as a precursor to other boron hydrides. It ...
– experimented with for some rocket fuels * Metal carbides **
Zirconium carbide Zirconium carbide ( Zr C) is an extremely hard refractory ceramic material, commercially used in tool bits for cutting tools. It is usually processed by sintering. Properties It has the appearance of a gray metallic powder with cubic crystal ...
– used in some rocket fuels, also a combustion instability suppressant *
Metalloid A metalloid is a type of chemical element which has a preponderance of properties in between, or that are a mixture of, those of metals and nonmetals. There is no standard definition of a metalloid and no complete agreement on which elements are ...
s **
Silicon Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic ...
– high flame temperature, burns producing molten glass, used in some ignition compositions and delay charges, commonly with
lead tetroxide Lead(II,IV) oxide, also called red lead or minium, is the inorganic compound with the formula Pb3O4. A bright red or orange solid, it is used as pigment, in the manufacture of batteries, and rustproof primer paints. It is an example of a mixed ...
**
Boron Boron is a chemical element with the symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the '' boron group'' it has t ...
– used in some ignition mixtures **
Antimony Antimony is a chemical element with the symbol Sb (from la, stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds have been known since ancient ti ...
– used in some fireworks for
glitter Glitter is an assortment of small, reflective particles that come in a variety of shapes, sizes, and colors. Glitter particles reflect light at different angles, causing the surface to sparkle or shimmer. Glitter is similar to confetti, sparkle ...
effects, toxic, burns bright white; usually used as 200–300 mesh; with potassium nitrate and sulfur produces white fires * Non-metallic inorganic **
Sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formul ...
– ignition promoter, increases burn rate; increases sensitivity to temperature, impact and friction, dangerous in combination with chlorates; commonly used with nitrates; used as an additive; may contain residual acids, combination with carbonates or other alkaline stabilizers is advised in acid-sensitive compositions **
Red phosphorus Elemental phosphorus can exist in several allotropes, the most common of which are white and red solids. Solid violet and black allotropes are also known. Gaseous phosphorus exists as diphosphorus and atomic phosphorus. White phosphorus Whit ...
– extremely dangerous, especially in combination with chlorates (
Armstrong's mixture Armstrong's mixture is a highly sensitive primary explosive. It is very friction-sensitive. Formulations vary, but one consists of 67% potassium chlorate, 27% red phosphorus, 3% sulfur, and 3% calcium carbonate. It is named for Sir William Armstr ...
); used in caps; also used in
match A match is a tool for starting a fire. Typically, matches are made of small wooden sticks or stiff paper. One end is coated with a material that can be ignited by friction generated by striking the match against a suitable surface. Wooden mat ...
es and some military infrared flares; toxic ** White phosphorus – used in
incendiary weapon Incendiary weapons, incendiary devices, incendiary munitions, or incendiary bombs are weapons designed to start fires or destroy sensitive equipment using fire (and sometimes used as anti-personnel weaponry), that use materials such as napalm, th ...
s and to make some military smoke screens, ignites spontaneously in air; even more toxic ** Calcium silicide – used in some special compositions ** Antimony trisulfide – ignition promoter; fine powder increases sensitivity, sharpens the boom of salutes; toxic and sensitive to static electricity; emits bright white light, crystals also used as a fuel in glitter compositions and in white comets and pyrotechnic stars. Sensitive to friction and impact; the degree of sensitisation depends on the oxidizer (sensitive to friction and impact with potassium chlorate, friction with potassium perchlorate, impact with ammonium perchlorate, and insensitive to either with potassium nitrate). **
Arsenic sulfide Arsenic sulfide may refer to: ...
( realgar) – toxic, sensitive to impact and friction. Used for
report A report is a document that presents information in an organized format for a specific audience and purpose. Although summaries of reports may be delivered orally, complete reports are almost always in the form of written documents. Usage In ...
compositions due to its sensitivity with chlorate even in small amounts. Used in yellow
smoke composition A smoke composition is a pyrotechnic composition designed primarily to generate smoke. Smoke compositions are used as obscurants or for generation of signaling smokes. Some are used as a payload of smoke bombs and smoke grenades. Obscurants Smok ...
s due to its low boiling point. ** Phosphorus trisulfide – used to make
match A match is a tool for starting a fire. Typically, matches are made of small wooden sticks or stiff paper. One end is coated with a material that can be ignited by friction generated by striking the match against a suitable surface. Wooden mat ...
es **
Calcium phosphide Calcium phosphide (CP) is the inorganic compound with the formula Ca3P2. It is one of several phosphides of calcium, being described as the salt-like material composed of Ca2+ and P3−. Other, more exotic calcium phosphides have the formula CaP, ...
– liberates
phosphine Phosphine (IUPAC name: phosphane) is a colorless, flammable, highly toxic compound with the chemical formula , classed as a pnictogen hydride. Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like rotting ...
when wet, used in some naval signal flares **
Potassium thiocyanate Potassium thiocyanate is the chemical compound with the molecular formula KSCN. It is an important salt of the thiocyanate anion, one of the pseudohalides. The compound has a low melting point relative to most other inorganic salts. Use in che ...
* Carbon-based **
Carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon ma ...
***
Charcoal Charcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, ...
– makes dim gold sparks ***
Graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on la ...
– also used as
opacifier An opacifier is a substance added to a material in order to make the ensuing system opaque. An example of a chemical opacifier is titanium dioxide (TiO2), which is used as an opacifier in paints, in paper, and in plastics. It has very high refract ...
in rocket fuels to prevent heat transfer by radiation into lower layers of fuels and avoid the related explosions ***
Carbon black Carbon black (subtypes are acetylene black, channel black, furnace black, lamp black and thermal black) is a material produced by the incomplete combustion of coal and coal tar, vegetable matter, or petroleum products, including fuel oil, fluid ...
– produces long lasting fine gold sparks in fireworks, also used as opacifier in rocket fuels ** Asphaltum – carbon-based fuel, also used as a binder. Some forms contain ammonia; should not be combined with chlorates. ** Wood flour * Organic chemicals ** Sodium benzoate – often used in
whistle mix A pyrotechnic composition is a substance or mixture of substances designed to produce an effect by heat, light, sound, gas/smoke or a combination of these, as a result of non-detonative self-sustaining exothermic chemical reactions. Pyrotechnic s ...
es together with potassium perchlorate ** Sodium salicylate – used in some whistle mixes **
Gallic acid Gallic acid (also known as 3,4,5-trihydroxybenzoic acid) is a trihydroxybenzoic acid with the formula C6 H2( OH)3CO2H. It is classified as a phenolic acid. It is found in gallnuts, sumac, witch hazel, tea leaves, oak bark, and other plants ...
– used in some whistle mixes; sensitive to impact and friction, there are safer alternatives ** Potassium picrate – used in some whistle compositions, safer than gallic acid but still dangerous, with heavy metals (e.g. lead) forms explosive salts **
Terephthalic acid Terephthalic acid is an organic compound with formula C6H4(CO2H)2. This white solid is a commodity chemical, used principally as a precursor to the polyester PET, used to make clothing and plastic bottles. Several million tonnes are produced an ...
– a fuel in some smoke compositions ** Hexamine – a low-reactivity, accessory fuel **
Anthracene Anthracene is a solid polycyclic aromatic hydrocarbon (PAH) of formula C14H10, consisting of three fused benzene rings. It is a component of coal tar. Anthracene is used in the production of the red dye alizarin and other dyes. Anthracene is co ...
– a fuel in some smoke compositions, produces black smoke **
Naphthalene Naphthalene is an organic compound with formula . It is the simplest polycyclic aromatic hydrocarbon, and is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08  ppm by mass. As an aromat ...
– a fuel in some smoke compositions **
Lactose Lactose is a disaccharide sugar synthesized by galactose and glucose subunits and has the molecular formula C12H22O11. Lactose makes up around 2–8% of milk (by mass). The name comes from ' (gen. '), the Latin word for milk, plus the suffix ' ...
– used together with potassium chlorate in many smoke compositions; cheap low-reactivity accessory fuel **
Dextrose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, usin ...
– used in some amateur solid rocket fuels **
Sucrose Sucrose, a disaccharide, is a sugar composed of glucose and fructose subunits. It is produced naturally in plants and is the main constituent of white sugar. It has the molecular formula . For human consumption, sucrose is extracted and refine ...
– used in some smoke compositions **
Sorbitol Sorbitol (), less commonly known as glucitol (), is a sugar alcohol with a sweet taste which the human body metabolizes slowly. It can be obtained by reduction of glucose, which changes the converted aldehyde group (−CHO) to a primary alcoho ...
– used together with potassium nitrate as an amateur solid rocket fuel ** Dextrin – also a binder ** Stearin,
stearic acid Stearic acid ( , ) is a saturated fatty acid with an 18-carbon chain. The IUPAC name is octadecanoic acid. It is a waxy solid and its chemical formula is C17H35CO2H. Its name comes from the Greek word στέαρ "''stéar''", which means ta ...
– accessory fuel, a possible replacement for charcoal and/or sulfur in some compositions; lengthens flames, can reduce friction sensitivity; phlegmatizing agent ** Hexachloroethane – used in many military smoke compositions * Organic polymers and resins, also sometimes serving as binders **
Teflon Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. It is one of the best-known and widely applied PFAS. The commonly known brand name of PTFE-based composition is Teflon by Chemo ...
, Viton and other
fluoropolymer A fluoropolymer is a fluorocarbon-based polymer with multiple carbon–fluorine bonds. It is characterized by a high resistance to solvents, acids, and bases. The best known fluoropolymer is polytetrafluoroethylene under the brand name "Tefl ...
s – sometimes also working as oxidizer – used in military pyrolant compositions, e.g. Magnesium/Teflon/Viton; extremely reactive in contact with some fine metal powders **
Hydroxyl-terminated polybutadiene Hydroxyl-terminated polybutadiene (HTPB) is an oligomer of butadiene terminated at each end with a hydroxyl functional group. It reacts with isocyanates to form polyurethane polymers. HTPB is a translucent liquid with a color similar to wax paper ...
(HTPB), used together with aluminium and ammonium nitrate in composite rocket fuels as a fuel and binder ** Carboxyl-terminated polybutadiene (CTPB), used in composite rocket fuels as a fuel and binder ** PBAN, used together with aluminium and ammonium nitrate in composite rocket fuels as a fuel and binder ** Polysulfide, used in composite rocket fuels as a fuel and binder **
Polyurethane Polyurethane (; often abbreviated PUR and PU) refers to a class of polymers composed of organic units joined by carbamate (urethane) links. In contrast to other common polymers such as polyethylene and polystyrene, polyurethane is produced from ...
, used in composite rocket fuels as a fuel and binder ** Polyisobutylene **
Nitrocellulose Nitrocellulose (also known as cellulose nitrate, flash paper, flash cotton, guncotton, pyroxylin and flash string, depending on form) is a highly flammable compound formed by nitrating cellulose through exposure to a mixture of nitric acid and ...
**
Polyethylene Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging ( plastic bags, plastic films, geomembranes and containers including b ...
** Polyvinyl chloride, also serving as chlorine donor and a binder ** Polyvinylidene chloride, also serving as chlorine donor ** Shellac, good especially for colored flame compositions ** Accroides resin ( red gum), higher burning rate than shellac, burns well even with potassium perchlorate. Suitable for chrysanthemum stars. When metallic fuels are used, the metal particle size is important. A larger surface area to volume ratio leads to a faster reaction; this means that smaller particle sizes produce a faster-burning composition. The shape also matters. Spherical particles, like those produced by atomizing molten metal, are undesirable. Thin and flat particles, like those produced by milling metal foil, have higher reaction surface and therefore are ideal when faster reaction is desired. Using
nanoparticles A nanoparticle or ultrafine particle is usually defined as a particle of matter that is between 1 and 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm, or fibers and tubes that are less than 10 ...
can drastically affect the reaction rates;
metastable intermolecular composite Nano-thermite or super-thermite is a metastable intermolecular composite (MIC) characterized by a particle size of its main constituents, a metal and a metal oxide, under 100 nanometers. This allows for high and customizable reaction rates. Nano-t ...
s exploit this. A suitable metal fuel may be dangerous on its own, even before it is mixed with an oxidizer. Careful handling is required to avoid the production of
pyrophoric A substance is pyrophoric (from grc-gre, πυροφόρος, , 'fire-bearing') if it ignites spontaneously in air at or below (for gases) or within 5 minutes after coming into contact with air (for liquids and solids). Examples are organolith ...
metal powders.


Oxidizers

Perchlorate A perchlorate is a chemical compound containing the perchlorate ion, . The majority of perchlorates are commercially produced salts. They are mainly used as oxidizers for pyrotechnic devices and to control static electricity in food packaging. ...
s,
chlorate The chlorate anion has the formula ClO3-. In this case, the chlorine atom is in the +5 oxidation state. "Chlorate" can also refer to chemical compounds containing this anion; chlorates are the salts of chloric acid. "Chlorate", when followed by ...
s and
nitrate Nitrate is a polyatomic ion with the chemical formula . Salts containing this ion are called nitrates. Nitrates are common components of fertilizers and explosives. Almost all inorganic nitrates are soluble in water. An example of an insolu ...
s are the most commonly used oxidizers for flash powders. Other possibilities include
permanganate A permanganate () is a chemical compound containing the manganate(VII) ion, , the conjugate base of permanganic acid. Because the manganese atom is in the +7 oxidation state, the permanganate(VII) ion is a strong oxidizing agent. The ion is a ...
s, chromates, and some
oxide An oxide () is a chemical compound that contains at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion of oxygen, an O2– (molecular) ion. with oxygen in the oxidation state of −2. Most of the E ...
s. Generally, the less the oxidizer, the slower the burning and the more light produced. For use at very high temperatures,
sulfate The sulfate or sulphate ion is a polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many ...
s can be used as oxidizers in combination with very strongly reducing fuels. Oxidizers in use include: *
Perchlorate A perchlorate is a chemical compound containing the perchlorate ion, . The majority of perchlorates are commercially produced salts. They are mainly used as oxidizers for pyrotechnic devices and to control static electricity in food packaging. ...
s (also serving as chlorine donors): **
Potassium perchlorate Potassium perchlorate is the inorganic salt with the chemical formula K Cl O4. Like other perchlorates, this salt is a strong oxidizer although it usually reacts very slowly with organic substances. This, usually obtained as a colorless, crysta ...
– common, relatively stable. Almost non-hygroscopic. Low solubility in water. Produces high temperature flame and smoke of potassium chloride. Safer replacement of potassium chlorate. Impact-sensitive with phosphorus, **
Ammonium perchlorate Ammonium perchlorate ("AP") is an inorganic compound with the formula Ammonium, NH4perchlorate, ClO4. It is a colorless or white solid that is soluble in water. It is a powerful oxidizer. Combined with a fuel, it can be used as a rocket propella ...
– the most common oxidizer for modern solid rocket fuels; more sensitive to mechanical stimuli than potassium perchlorate. Uncommon in fireworks; creates hot flame, enhances barium, strontium and copper colorants by acting as a chlorine donor. Reacts with magnesium when wet and liberates heat and ammonia, can self-ignite. In contact with potassium nitrate (e.g. in black powder) produces potassium perchlorate and
hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance' ...
ammonium nitrate; no such reaction with sodium nitrate. Reacts with potassium chlorate, producing unstable, gradually decomposing ammonium chlorate; such combination has to be avoided. **
Nitronium perchlorate Nitronium perchlorate, NO2ClO4, also known as nitryl perchlorate and nitroxyl perchlorate, is an inorganic chemical, the salt of the perchlorate anion and the nitronium cation. It forms colorless monoclinic crystals. It is hygroscopic, and is a s ...
*
Chlorate The chlorate anion has the formula ClO3-. In this case, the chlorine atom is in the +5 oxidation state. "Chlorate" can also refer to chemical compounds containing this anion; chlorates are the salts of chloric acid. "Chlorate", when followed by ...
s (also serving as chlorine donors, incompatible with ammonium salts because of forming unstable explosive ammonium chlorate, incompatible with sulfur and other acidic chemicals because of production of spontaneously igniting chlorine dioxide; very dangerous with phosphorus; should not be combined with hydrocarbon fuels/binders, e.g. asphalt or gum arabic; should be replaced with safer perchlorates wherever possible): **
Potassium chlorate Potassium chlorate is a compound containing potassium, chlorine and oxygen, with the molecular formula KClO3. In its pure form, it is a white crystalline substance. After sodium chlorate, it is the second most common chlorate in industrial use. ...
– much less stable than perchlorate, hazardous, avoid if possible. High burning speed, easy ignition. Slightly more hygroscopic than potassium nitrate. Produces smoke of potassium chloride. Can act as a chlorine donor. High impact and friction sensitivity with sulfur and sulfides. With ammonium salts produces unstable ammonium chlorate. Used in match head compositions, some colored smokes, and small firecrackers and toy caps. ** Barium chlorate – also serves as a green colorant in fireworks; sensitive, better to avoid. Almost non-hygroscopic. Compositions may spontaneously combust in sunlight. Very good green colorant, even in lower-temperature flames. ** Sodium chlorate – much less stable than perchlorate, hazardous, also serves as yellow colorant,
hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance' ...
*
Nitrate Nitrate is a polyatomic ion with the chemical formula . Salts containing this ion are called nitrates. Nitrates are common components of fertilizers and explosives. Almost all inorganic nitrates are soluble in water. An example of an insolu ...
s (when mixing with aluminium, boric acid should be added as a stabilizer): **
Potassium nitrate Potassium nitrate is a chemical compound with the chemical formula . This alkali metal nitrate salt is also known as Indian saltpetre (large deposits of which were historically mined in India). It is an ionic salt of potassium ions K+ and ...
– very common, used in
black powder Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, carbon (in the form of charcoal) and potassium nitrate (saltpeter). T ...
and wide variety of compositions. Not very hygroscopic. At lower temperatures (with ordinary fuels like rosin or shellac) not very efficient, does not burn well, produces potassium nitrite. At higher temperatures, with charcoal and sulfur or with magnesium, decomposes well. Does not produce sufficient temperature to make colored flames, except when magnesium is added. Makes good sparks. Presence in dust makes the dust hazardous and very flammable. **
Sodium nitrate Sodium nitrate is the chemical compound with the formula . This alkali metal nitrate salt is also known as Chile saltpeter (large deposits of which were historically mined in Chile) to distinguish it from ordinary saltpeter, potassium nitrate. ...
– also a yellow colorant, hygroscopic. Gives intense yellow light, used for illumination compositions. Presence in dust makes the dust hazardous. At lower temperatures produces nitrite ash, at higher temperatures decomposes completely. ** Calcium nitrate – also a red-orange colorant. **
Ammonium nitrate Ammonium nitrate is a chemical compound with the chemical formula . It is a white crystalline salt consisting of ions of ammonium and nitrate. It is highly soluble in water and hygroscopic as a solid, although it does not form hydrates. It is ...
– used in some less common composite rocket propellants, hygroscopic, decomposes at too low temperature; when dry reacts with Al, Zn, Pb, Sb, Bi, Ni, Cu, Ag, Cd; when wet reacts also with Fe. Forms an explosive compound with copper. ** Barium nitrate – most common oxidizer/colorant for green and white colors, but with somewhat weak colorant effect;requires a chlorine donor. Also used in flash powders and some military infrared flares. Barium also serves as a stabilizer for the mixtures; decomposes at higher temperatures than nitrates of lighter metals and promotes higher burning temperatures. With aluminium produces bright silver sparks; when used with aluminium, addition of boric acid as stabilizer is advised. Not very hygroscopic. ** Strontium nitrate – most common oxidizer/colorant for red colors in flares, fires, and stars; strontium also serves as a stabilizer for the mixtures. At lower temperatures (with organic fuels) produces strontium nitrite ash which can smother the flame; decomposes completely at higher temperatures (with magnesium). Colorant for low-temperature flames, colorant and oxidizer for hot flames. ** Caesium nitrate – used in some military infrared flare compositions *
Permanganate A permanganate () is a chemical compound containing the manganate(VII) ion, , the conjugate base of permanganic acid. Because the manganese atom is in the +7 oxidation state, the permanganate(VII) ion is a strong oxidizing agent. The ion is a ...
s: ** Potassium permanganate – used in early mixtures, now considered to be sensitive and unstable **
Ammonium permanganate Ammonium permanganate is the chemical compound NH4MnO4, or NH3· HMnO4. It is a water soluble, violet-brown or dark purple salt. Preparation Ammonium permanganate was first prepared by Eilhard Mitscherlich in 1824 by reaction of silver perma ...
– a moderately powerful explosive * Chromates: ** Barium chromate – used in delay compositions, e.g. in fireworks rockets ** Lead chromate – used in delay compositions ** Potassium dichromate – used infrequently as an oxidizer; can be used as a surface treatment for passivation of magnesium particles, also as a catalyst and in some matches; potassium perchlorate often added *
Oxide An oxide () is a chemical compound that contains at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion of oxygen, an O2– (molecular) ion. with oxygen in the oxidation state of −2. Most of the E ...
s and
peroxide In chemistry, peroxides are a group of compounds with the structure , where R = any element. The group in a peroxide is called the peroxide group or peroxo group. The nomenclature is somewhat variable. The most common peroxide is hydrogen p ...
s: ** Barium peroxide – unstable, spontaneously decomposes, compositions containing it should not be stored **
Strontium peroxide Strontium peroxide is an inorganic compound with the formula Sr O2 that exists in both anhydrous and octahydrate form, both of which are white solids. The anhydrous form adopts a structure similar to that of calcium carbide. Uses It is an oxidi ...
**
Lead tetroxide Lead(II,IV) oxide, also called red lead or minium, is the inorganic compound with the formula Pb3O4. A bright red or orange solid, it is used as pigment, in the manufacture of batteries, and rustproof primer paints. It is an example of a mixed ...
– versatile but toxic ** Lead dioxide – used in friction-sensitive compositions, e.g.
match A match is a tool for starting a fire. Typically, matches are made of small wooden sticks or stiff paper. One end is coated with a material that can be ignited by friction generated by striking the match against a suitable surface. Wooden mat ...
es **
Bismuth trioxide Bismuth(III) oxide is perhaps the most industrially important compound of bismuth. It is also a common starting point for bismuth chemistry. It is found naturally as the mineral bismite (monoclinic) and sphaerobismoite (tetragonal, much more rare) ...
– used as a safe alternative to lead tetroxide in some compositions **
Iron(III) oxide Iron(III) oxide or ferric oxide is the inorganic compound with the formula Fe2O3. It is one of the three main oxides of iron, the other two being iron(II) oxide (FeO), which is rare; and iron(II,III) oxide (Fe3O4), which also occurs naturally a ...
– a high temperature oxidizer, a catalyst **
Iron(II,III) oxide Iron(II,III) oxide is the chemical compound with formula Fe3O4. It occurs in nature as the mineral magnetite. It is one of a number of iron oxides, the others being iron(II) oxide (FeO), which is rare, and iron(III) oxide (Fe2O3) which also occu ...
– an oxidizer in Thermite and Thermate **
Manganese(IV) oxide Manganese dioxide is the inorganic compound with the formula . This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for is for dry-c ...
– an oxidizer in manganese thermite, a catalyst ** Chromium(III) oxide – an oxidizer in chromium thermite ** Tin(IV) oxide – an oxidizer in some delay charges *
Sulfate The sulfate or sulphate ion is a polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many ...
s (reactions require high temperatures and strongly reducing fuels): **
Barium sulfate Barium sulfate (or sulphate) is the inorganic compound with the chemical formula Ba SO4. It is a white crystalline solid that is odorless and insoluble in water. It occurs as the mineral barite, which is the main commercial source of barium and ...
– a high-temperature oxidizer for e.g. strobe compositions, a green colorant **
Calcium sulfate Calcium sulfate (or calcium sulphate) is the inorganic compound with the formula CaSO4 and related hydrates. In the form of γ-anhydrite (the anhydrous form), it is used as a desiccant. One particular hydrate is better known as plaster of Paris ...
– a high-temperature oxidizer for e.g. strobe compositions, a red-orange colorant. ** Potassium sulfate – a high-temperature oxidizer, a purple colorant **
Sodium sulfate Sodium sulfate (also known as sodium sulphate or sulfate of soda) is the inorganic compound with formula Na2SO4 as well as several related hydrates. All forms are white solids that are highly soluble in water. With an annual production of 6 mil ...
– a high-temperature oxidizer, a yellow colorant ** Strontium sulfate – a high-temperature oxidizer, a red colorant * Organic chemicals **
Guanidine nitrate Guanidine nitrate is the chemical compound with the formula (NH2)3O3. It is a colorless, water-soluble salt. It is produced on a large scale and finds use as precursor for nitroguanidine, fuel in pyrotechnics and gas generators. Its correct ...
– used in some high power rocket fuels, propellants, and blue firework compositions **
Hexanitroethane Hexanitroethane (HNE) is an organic compound with chemical formula C2N6O12 or (O2N)3C-C(NO2)3. It is a solid matter with a melting point of 135 °C. Hexanitroethane is used in some pyrotechnic compositions as a nitrogen-rich oxidizer, e.g. in s ...
– used in some special military compositions **
Cyclotrimethylene trinitramine RDX (abbreviation of "Research Department eXplosive") or hexogen, among other names, is an organic compound with the formula (O2N2CH2)3. It is a white solid without smell or taste, widely used as an explosive. Chemically, it is classified as a n ...
– used in some double-base propellants **
Cyclotetramethylene Tetranitramine HMX, also called octogen, is a powerful and relatively insensitive nitroamine high explosive, chemically related to RDX. Like RDX, the compound's name is the subject of much speculation, having been variously listed as High Melting Explosive, ...
– used in some double-base propellants * Others **
Sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formul ...
– oxidizer for zinc in zinc-sulfur fuels **
Teflon Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. It is one of the best-known and widely applied PFAS. The commonly known brand name of PTFE-based composition is Teflon by Chemo ...
– oxidizer for some metal fuels **
Boron Boron is a chemical element with the symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the '' boron group'' it has t ...
– oxidizer for titanium, forming titanium diborideEnergyStorm – Titanium-boron mixtures as variable heat sources
. Energystorm.us. Retrieved on 2010-10-15.
Corresponding sodium salts can be substituted for potassium ones.


Additives

* Coolants. For some purposes it is necessary to lower the burning temperature of the mixture, and/or slow down the reaction rate. For such purpose, inert materials (e.g.
clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay pa ...
,
diatomaceous earth Diatomaceous earth (), diatomite (), or kieselgur/kieselguhr is a naturally occurring, soft, siliceous sedimentary rock that can be crumbled into a fine white to off-white powder. It has a particle size ranging from more than 3 μm to l ...
, alumina,
silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is ...
,
magnesium oxide Magnesium oxide ( Mg O), or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium (see also oxide). It has an empirical formula of MgO and consists of a lattice of Mg2+ ions and O2� ...
, or others) or endothermically decomposing materials (e.g.
carbonate A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate ...
s) are added.
Oxamide Oxamide is the organic compound with the formula . This white crystalline solid is soluble in ethanol, slightly soluble in water and insoluble in diethyl ether. Oxamide is the diamide derived from oxalic acid. Preparation Oxamide is produced fr ...
is used as a high performance burning rate suppressant in some propellant compositions. Strontium carbonate is used as a fire retardant in some gunpowders. * Flame suppressants.
Potassium nitrate Potassium nitrate is a chemical compound with the chemical formula . This alkali metal nitrate salt is also known as Indian saltpetre (large deposits of which were historically mined in India). It is an ionic salt of potassium ions K+ and ...
and potassium sulfate are commonly used. *
Opacifier An opacifier is a substance added to a material in order to make the ensuing system opaque. An example of a chemical opacifier is titanium dioxide (TiO2), which is used as an opacifier in paints, in paper, and in plastics. It has very high refract ...
s. Some solid rocket propellants have problems with radiative heat transfer through the material, which may lead to explosion.
Carbon black Carbon black (subtypes are acetylene black, channel black, furnace black, lamp black and thermal black) is a material produced by the incomplete combustion of coal and coal tar, vegetable matter, or petroleum products, including fuel oil, fluid ...
and
graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on la ...
are often used to inhibit this effect. * Colorants, sometimes in combination with sources of
chlorine Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine i ...
. Usually salts of suitable metals, often
barium Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element. Th ...
,
strontium Strontium is the chemical element with the symbol Sr and atomic number 38. An alkaline earth metal, strontium is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is e ...
,
calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar ...
,
sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...
,
copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pink ...
, etc. The salt may simultaneously serve as an oxidizer.
Copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pink ...
metal can be also used. Copper acetoarsenite with potassium perchlorate provides richest blue. * Chlorine donors. Used together with colorants. In some cases, the color emitting species is molecular and not atomic. Such is the case for blue pyrotechnic flames where the emitting species is copper monochloride. Also, some chloride molecular emitters are much stronger than oxides of the same element, as in the case of Barium and Strontium. Polyvinyl chloride, polyvinylidene chloride, Saran, chlorinated paraffins, chlorinated
rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and ...
(e.g. Parlon), hexachloroethane,
hexachlorobenzene Hexachlorobenzene, or perchlorobenzene, is an organochloride with the molecular formula C6Cl6. It is a fungicide formerly used as a seed treatment, especially on wheat to control the fungal disease bunt. It has been banned globally under the Sto ...
(most common chlorine donor until the 1970s, now rarely used), and some other organochlorides and inorganic
chloride The chloride ion is the anion (negatively charged ion) Cl−. It is formed when the element chlorine (a halogen) gains an electron or when a compound such as hydrogen chloride is dissolved in water or other polar solvents. Chloride s ...
s (e.g. ammonium chloride,
mercurous chloride Mercury(I) chloride is the chemical compound with the formula Hg2Cl2. Also known as the mineral calomel (a rare mineral) or mercurous chloride, this dense white or yellowish-white, odorless solid is the principal example of a mercury(I) compound. ...
) are used as chlorine donors. Perchlorates and chlorates play this role together with their main use as oxidizers. Chlorine donors are often used also in
smoke composition A smoke composition is a pyrotechnic composition designed primarily to generate smoke. Smoke compositions are used as obscurants or for generation of signaling smokes. Some are used as a payload of smoke bombs and smoke grenades. Obscurants Smok ...
s, e.g. hexachloroethane together with zinc oxide to produce smoke based on
zinc chloride Zinc chloride is the name of inorganic chemical compounds with the formula ZnCl2 and its hydrates. Zinc chlorides, of which nine crystalline forms are known, are colorless or white, and are highly soluble in water. This salt is hygroscopic ...
. *
Catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
s. Propellant formulas often require a catalyst to burn faster and more stably.
Transition metal In chemistry, a transition metal (or transition element) is a chemical element in the d-block of the periodic table (groups 3 to 12), though the elements of group 12 (and less often group 3) are sometimes excluded. They are the elements that can ...
ions and complexes tend to be used. Certain oxidizers often serve as catalysts. E.g. ammonium dichromate is used as a catalyst in ammonium nitrate based propellant formulas. Other catalysts are e.g.
iron(III) oxide Iron(III) oxide or ferric oxide is the inorganic compound with the formula Fe2O3. It is one of the three main oxides of iron, the other two being iron(II) oxide (FeO), which is rare; and iron(II,III) oxide (Fe3O4), which also occurs naturally a ...
, hydrated ferric oxide,
manganese dioxide Manganese dioxide is the inorganic compound with the formula . This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for is for dry-ce ...
, potassium dichromate, copper chromite, lead salicylate, lead stearate, lead 2-ethylhexoate, copper salicylate, copper stearate, lithium fluoride, n-butyl ferrocene, di-n-butyl ferrocene. *
Stabilizers Stabilizer, stabiliser, stabilisation or stabilization may refer to: Chemistry and food processing * Stabilizer (chemistry), a substance added to prevent unwanted change in state of another substance ** Polymer stabilizers are stabilizers used ...
. Some mixtures, e.g. containing chlorates, tend to degrade and create acidic byproducts.
Carbonate A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate ...
s (e.g.
sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...
,
calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar ...
, or barium carbonate) or other mildly alkaline materials can be added to scavenge such acids. Boric acid can be used to inhibit the sensitivity of aluminium to moisture, and to stabilize mixtures of metals with nitrates (which can otherwise form amides which react exothermically with metals and can cause spontaneous initiation). Many organic nitrated amines are used as stabilizers as well, e.g. 2-nitrodiphenylamine.
Petroleum jelly Petroleum jelly, petrolatum, white petrolatum, soft paraffin, or multi-hydrocarbon, CAS number 8009-03-8, is a semi-solid mixture of hydrocarbons (with carbon numbers mainly higher than 25), originally promoted as a topical ointment for its h ...
, castor oil,
linseed oil Linseed oil, also known as flaxseed oil or flax oil (in its edible form), is a colourless to yellowish oil obtained from the dried, ripened seeds of the flax plant (''Linum usitatissimum''). The oil is obtained by pressing, sometimes followed by ...
, etc. can be used as stabilizers, also to add hydrophobicity to particles and protect metals (especially iron and magnesium) from corrosion.
Ethyl centralite Centralite (empirical formula: C17H20N2O) is a gunshot residue also known as ethyl centralite. Its IUPAC name is 1,3-diethyl-1,3-diphenylurea. Ethyl centralite is insoluble in water, but is soluble in acetone, ethanol and benzene. It is mainly us ...
and 2-nitrodiphenylamine are used in some rocket propellants. *
Anticaking agent An anticaking agent is an additive placed in powdered or granulated materials, such as table salt or confectioneries, to prevent the formation of lumps (caking) and for easing packaging, transport, flowability, and consumption. Caking mechanisms ...
s. E.g.
fumed silica Fumed silica (CAS_Registry_Number, CAS number 112945-52-5), also known as pyrogenic silica because it is produced in a flame, consists of microscopic droplets of amorphous silica fused into branched, chainlike, three-dimensional secondary partic ...
. For powder compositions, e.g. flash powder or
gunpowder Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, carbon (in the form of charcoal) and potassium nitrate (saltpeter). T ...
.
Graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on la ...
is used in some cases to coat the grains, lubricate them, and dissipate
static electricity Static electricity is an imbalance of electric charges within or on the surface of a material or between materials. The charge remains until it is able to move away by means of an electric current or electrical discharge. Static electricity is na ...
.
Magnesium carbonate Magnesium carbonate, (archaic name magnesia alba), is an inorganic salt that is a colourless or white solid. Several hydrated and basic forms of magnesium carbonate also exist as minerals. Forms The most common magnesium carbonate forms are ...
used too, together with its function as carbonate stabilizer. * Binders. Often gums and
resin In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on nat ...
s, e.g. gum arabic, red gum, guar gum, copal,
carboxymethyl cellulose Carboxymethyl cellulose (CMC) or cellulose gum is a cellulose derivative with carboxymethyl groups (-CH2-COOH) bound to some of the hydroxyl groups of the glucopyranose monomers that make up the cellulose backbone. It is often used as its sodiu ...
,
nitrocellulose Nitrocellulose (also known as cellulose nitrate, flash paper, flash cotton, guncotton, pyroxylin and flash string, depending on form) is a highly flammable compound formed by nitrating cellulose through exposure to a mixture of nitric acid and ...
, rice
starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human die ...
,
cornstarch Corn starch, maize starch, or cornflour (British English) is the starch derived from corn (maize) grain. The starch is obtained from the endosperm of the kernel. Corn starch is a common food ingredient, often used to thicken sauces or sou ...
, shellac, dextrin. Binders can also serve as fuels.
Camphor Camphor () is a waxy, colorless solid with a strong aroma. It is classified as a terpenoid and a cyclic ketone. It is found in the wood of the camphor laurel (''Cinnamomum camphora''), a large evergreen tree found in East Asia; and in the k ...
can be used as a
plasticizer A plasticizer ( UK: plasticiser) is a substance that is added to a material to make it softer and more flexible, to increase its plasticity, to decrease its viscosity, and/or to decrease friction during its handling in manufacture. Plasticiz ...
. Binders are used in manufacture of compact compositions, e.g. pyrotechnic stars. Polymers like HTPB and PBAN are often used for rocket fuels. Other polymers used are e.g.
polyethylene Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging ( plastic bags, plastic films, geomembranes and containers including b ...
or polyvinyl chloride can be encountered as well. *
Plasticizer A plasticizer ( UK: plasticiser) is a substance that is added to a material to make it softer and more flexible, to increase its plasticity, to decrease its viscosity, and/or to decrease friction during its handling in manufacture. Plasticiz ...
s. Improve the mechanical properties of the propellant particles. For composite rocket propellants,
dioctyl adipate Dioctyl adipate (DOA) is an organic compound with the formula (CH2CH2CO2C8H17)2. It is a colorless oily liquid. As well as related diesters derived from 2-ethylhexanol, decanol, isodecanol, etc., it is used as a plasticizer. DEHA is sometimes ...
, isodecyl pelargonate, and
dioctyl phthalate Bis(2-ethylhexyl) phthalate (di-2-ethylhexyl phthalate, diethylhexyl phthalate, diisooctyl phthalate, DEHP; incorrectly — dioctyl phthalate, DIOP) is an organic compound with the formula C6H4(CO2C8H17)2. DEHP is the most common member of the cl ...
are often used. Plasticizers can also be other energetic materials (common in smokeless powders), e.g. nitroglycerine, butanetriol trinitrate,
dinitrotoluene Dinitrotoluenes could refer to one of the following compounds: * 2,3-Dinitrotoluene * 2,4-Dinitrotoluene 2,4-Dinitrotoluene (DNT) or dinitro is an organic compound with the formula C7H6N2O4. This pale yellow crystalline solid is well known as a ...
, trimethylolethane trinitrate, diethylene glycol dinitrate, triethylene glycol dinitrate, bis(2,2-dinitropropyl)formal, bis(2,2-dinitropropyl)acetal, 2,2,2-trinitroethyl 2-nitroxyethyl ether, and others. * Curing and crosslinking agents. Used to harden the polymer component of composite rocket propellants. They include paraquinone dioxime, toluene-2,4-diisocyanate, tris(1-(2-methyl) aziridinyl) phosphine oxide, N,N,O-tri(1,2-epoxy propyl)-4-aminophenol, and isophorone diisocyanate. * Bonding agents. Used to increase the level of bonding between the binder and the fuel/oxidizer particles. They include tris(1-(2-methyl) azirinidyl) phosphine oxide and
triethanolamine Triethanolamine, or TEA is a viscous organic compound that is both a tertiary amine and a triol. A triol is a molecule with three alcohol groups. Approximately 150,000 tonnes were produced in 1999. It is a colourless compound although samples m ...
.


See also

* Thermite * Nano-thermite * Thermate


References


External links


A pyroguide article on Pyrotechnic composition
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