A pyrolant (from Greek ''pyr'', fire) is an energetic material that generates hot
flames upon
combustion
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion ...
. Pyrolants are metal-based
pyrotechnic composition
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 reaction, exothermic chemical reac ...
s containing virtually any oxidizer.
The term was originally coined by Kuwahara in 1992, in a paper on
magnesium/Teflon/Viton, to distinguish between compositions that serve as propellants and those yielding hot flames which are not necessarily suitable for propellant purposes.
''
Thermite
Thermite () is a pyrotechnic composition of powder metallurgy, metal powder and metal oxide. When ignited by heat or chemical reaction, thermite undergoes an exothermic redox, reduction-oxidation (redox) reaction. Most varieties are not explos ...
s'' constitute a subdivision of pyrolants referring to mixtures containing a narrow range of oxygen-based oxidizers only, Hence the term thermite cannot be used interchangeably with "pyrolant".
A similar common term is ''
propellant
A propellant (or propellent) is a mass that is expelled or expanded in such a way as to create a thrust or another motive force in accordance with Newton's third law of motion, and "propel" a vehicle, projectile, or fluid payload. In vehicle ...
'', which describes either a homogeneous or composite material that generates thrust upon combustion, but which may contain fuels instead of or in addition to the metals contained in
thermite
Thermite () is a pyrotechnic composition of powder metallurgy, metal powder and metal oxide. When ignited by heat or chemical reaction, thermite undergoes an exothermic redox, reduction-oxidation (redox) reaction. Most varieties are not explos ...
s.
Pyrolants are generally characterized by high combustion temperatures (> 2000 K) and high amounts of condensed reaction products at equilibrium conditions such as metal
oxide
An oxide () is a chemical compound containing at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion (anion bearing a net charge of −2) of oxygen, an O2− ion with oxygen in the oxidation st ...
s,
fluoride
Fluoride (). According to this source, is a possible pronunciation in British English. is an Inorganic chemistry, inorganic, Monatomic ion, monatomic Ion#Anions and cations, anion of fluorine, with the chemical formula (also written ), whose ...
s and
soot
Soot ( ) is a mass of impure carbon particles resulting from the incomplete combustion of hydrocarbons. Soot is considered a hazardous substance with carcinogenic properties. Most broadly, the term includes all the particulate matter produced b ...
.
Typical pyrolants find use as
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. Th ...
s (
Zr/
BaCrO4 or Zr/
KClO4),
illuminating flare (
Mg/
NaNO3) and
decoy flare
A flare or decoy flare is an aerial infrared countermeasure used by an aircraft to counter an infrared homing ("heat-seeking") surface-to-air missile or air-to-air missile. Flares are commonly composed of a pyrotechnic composition based on mag ...
compositions (Mg/
(C2F4)n)
E.-C. Koch Metal/Fluorocarbon Pyrolants: VI. Combustion Behaviour and Radiation Properties of Magnesium/Poly(Carbon Monofluoride) Pyrolant, Prop''., Explos., Pyrotech. 30'' 2005 209.
References
Military technology
Pyrotechnic compositions