Formulations pyrotechnic

STOICHIOMETRIC MIXTURE A balanced mixture which, on reaction, will yield a stoichiometric compound. For example, two molecules of hydrogen and one molecule of oxygen constitute a stoichiometric mixture because they yield exactly two molecules of water on combustion. Such a balance is important when formulating pyrotechnic compositions. 

Cost is always a factor in selecting a component for a pyrotechnic composition, as is the water-attracting abiHty of a substance (hygroscopicity). In general, substances that attract water from the atmosphere are avoided in pyrotechnic formulations for a variety of reasons, thereby supporting the centuries-old adage, "Keep your powder dry."... 

Another matter of concern in pyrotechnic formulations is the possibiHty of exchange reactions occurring between components. Addition of ammonium salts to compositions containing nitrate oxidizers can produce ammonium nitrate, a very hygroscopic material. The composition then becomes quite prone to pick up water and its performance deteriorates. The addition of an ammonium salt to a chlorate-based formulation can lead to the... 

The air bag industry has become one of the principal users of pyrotechnic compositions in the world. Most of the current air bag systems are based on the thermal decomposition of sodium azide, NaN, to rapidly generate a large volume of nitrogen gas, N2. Air bag systems must function immediately (within 50 ms) upon impact, and must quickly deploy a pulse of reasonably cool, nontoxic, unreactive gas to inflate the protective cushion for the driver or passenger. These formulations incorporate an oxidizer such as iron oxide to convert the atomic sodium that initially forms into sodium oxide, Na20. Equation 1 represents the reaction. 

Sodium nitrate is also used in formulations of heat-transfer salts for he at-treatment baths for alloys and metals, mbber vulcanization, and petrochemical industries. A mixture of sodium nitrate and potassium nitrate is used to capture solar energy (qv) to transform it into electrical energy. The potential of sodium nitrate in the field of solar salts depends on the commercial development of this process. Other uses of sodium nitrate include water (qv) treatment, ice melting, adhesives (qv), cleaning compounds, pyrotechnics, curing bacons and meats (see Food additives), organics nitration, certain types of pharmaceutical production, refining of some alloys, recovery of lead, and production of uranium. 

A water-soluble white crystalline sofld, CS is disseminated as a spray, as a cloud of dust or powder, or as an aerosol generated thermally from pyrotechnic compositions. The formulation designated CSl is CS mixed with an anti-agglomerant when dusted on the ground, it may remain active for as long as five days. CS2 formulated from CSl and a siUcone water repellent, may persist for as long as 45 days (6). 

Other uses of hexachloroethane are as moth repellent, plasticizer for cellulose esters, anthelmintic in veterinary medicine, mbber accelerator, and as a component in fungicidal and insecticidal formulations. Hexachloroethane reacts with silumin (an aluminum /siUcon alloy) at 483 K to generate an intense white smoke, which is useful in certain pyrotechnics (154). 

Small arms ammo can be so severely affected by moisture that a special indicating lacquer was developed for 20mm rounds which changes color from grey to black on w exposure (Ref 59) Effect of Moisture on Pyrotechnics Pyrot formulations usually contain finely powdered metal fuels such as Mg, Al, Fe, Cu, etc, all of which can react with moisture to yield H2. This effect has been dubbed gassing in pyrot circles, and is the major problem associated with the storage of hermetically sealed ammo of this... 

Parlon has been used in pyrotechnic tracer formulations as a color intensifier and binder (Ref 4). It is also employed as a base for rapid drying concrete paints and alkyd enamels (Ref 5) Refs 1) G.F. Bloomfield, JChemSoc 1943, 289 2) Parlon, Properties and Uses , Hercules... 

Flares, Signaling Devices, and other Pyrotechnics. A large number of formulations contg K perchlorate have been reported. Some devices which use these are red RR signal flares (Refs 2 22, p 275) parachute flares (Ref 6) stars for use in signaling pistols (Very pistols) (Refs 5. 22, p 275) variously colored flares (Refs 19, pp 197-8 22, p 275) stars and other components of display fireworks (Refs 16 32) ... 

Red P has been employed as an ingredient of pyrotechnic smoke, delay and safety match formulations (Refs 1,2,3 4). White smoke consisting of small droplets of phosphoric acid have been widely used for military purposes. 

Properties and Other Characteristics of Several Polyester Resin Binders Used in Pyrotechnic Formulations , Rept No RDTR No 51, USNAD, Crane (1966) 13a) V.V. Korshak et al, Poly-... 

Photoflash compns containing Hf and K perchlorate possess greater luminous efficiency on a volume basis than do other formulations (Ref 128). Zr, for example, when burned in oxygen has an average color temp of 4883°K compared with 5235°K for Hf when measured at peak intensity (Ref 65). In pyrotechnic flash units, substitution of Al with Hf and Ti produced comparable peak output, but inferior output... 

New process technologies (Ref 53) such as jet mills (Fig 2) and co-precipitation (Ref 97) may allow safe compounding of sensitive or toxic formulations. New analytical tools such as neutron radiography (Ref 92) afford improved non-destructive testing of devices. X-ray fluorescence (Ref 93) and neutron activation (Ref 94) provide quantitative analysis of pyrotechnic compns and their trace contaminants... 

During investigation of pyrotechnic flare formulations, it was found that mixtures of the metal powder and oxidant underwent a low-temperature exothermic reaction at 70-135°C in presence of moisture. 

For onsite analysis, the examination of the vast number of samples necessitates the use of quick, reliable, field portable equipment that can rapidly, quantitatively verify the many chemically different types of ammunition, explosives, and pyrotechnics. The most common suite of analytes to detect is large, consisting of very chemically different compounds and usually occurs at trace levels in complex environmental matrices. This suite encompasses smokeless powders, black powders, and numerous propellant and energetic formulations. Detection should also be sought for common decomposition products of these explosives such as the methylanalines, aminonitrotoluenes, nitrotoluenes, mono- and dinitoroglycerines, and the nitrobenzenes under on-site conditions. 

Pyrotechnics are often used in the production of fireworks and primers. A pyrotechnic contains both a fuel and an oxidizer formulated to produce a lot of energy. The energy is then used to produce a flame or glow (matchstick) or combined with other volatile substances to produce smoke and light (fireworks) or large quantities of gas (firework rockets). 

J. P. Agrawal, V. K. Bapat, R. Daniel and R. G. Sarawadekar, A Comparative Study of Properties of PNP and NC Based Pyrotechnic Formulations , Proc. 34th International Annual Conference of ICT, Karlsruhe, Germany, June 24—27, 2003, p 64/1-64/13. 

Simoes, P., Pedroso, L., Portugal, A., Carvalheira, P., and Campos, J., New Propellant Component, Part I. Study of 4,6-Dinitroamino-l,3,5-triazine-2(lH)-one (DNAM), Propellants, Explosives, Pyrotechnics, Vol. 26, 2001, pp. 273-277 Simoes, P., Pedroso, L., Portugal, A., Plaksin, I., and Campos, J., New Propellant Component, Part I. Study of a PSAN/DNAM/HTPB Based Formulation, Propellants, Explosives, Pyrotechnics,... 

It should be mentioned that whereas chlorates faded away from the explosives scene, they found a broad range of applications in the pyrotechnic industry. Numerous commercial flash powders consist of KCIO3 and aluminum to this day. They are still exceedingly sensitive and are perhaps one of the biggest sources of accidents in the industry. Over time, numerous formulations started using potassium perchlorate (KCIO4) as a substitute. Perchlorates tend to be much less sensitive to insult than chlorates. 

As mentioned earlier, chlorates are also a major ingredient in various pyrotechnic formulations. Typically potassium chlorate is utilized in this capacity due to the more hygroscopic nature of the sodium analog. Mixed with powdered aluminum and/or sulfur, potassium chlorate produces a mixture commonly referred... 

The oldest and still widely used in pyrotechnics and fireworks "first fire" and "starter" mixture is BkPdr. It belongs to mixts without metallic ingredients. Metallic mixts contain combustible powdered metals, such as Mg, Al, Zr etc. Metalloids B and Si are considered metallic fuels because of their similarity in pyrochemical behavior to metals. Although BkPdrs are described in Vol 2 of Encycl, pp Bl65ff, we are giving here as Table E compns of three formulations used in pyrotechnics, as described by Ellern (Ref 57, p 375)... 

When used with highly compacted main pyrotechnic items, such as flare candles the "first fire" is either pressed (in dry form), or painted (in paste or slurry form) on top of item. For initiation of solid proplnts, a "first fire " mixt can be ignited if confined in a tube or capsule so that the hot gases will be spread over a larger surface area (Ref 57, pp 189 91) Table F lists various formulations for "starter mixtures" Table G for "ignition mixtures" and Table H for "first fire mixtures". -These formulations are given in Ref 57, pp 377-83. Some mixtures are taken from Ref 44a,... 

Four pyrotechnic delay compositions given in 1961 edition of Ellern (Ref 44a) are listed in Vol 3 of Encycl, p D50. In regard to Exotic" Delay Mixtures, Dr Ellern remarks in the 1968 ed of his book (Ref 57, p 415), that these formulations were actually prepd and tested in his laboratory, but the limited investigation was not further pursued by him or by others. At the time of development of Nb(Cb)-Ta - Ba Chromate mixts, the delay mixts with Cr, Mo W(Tungsten) were classified in US. That is why Dr Ellern develops his own mixts which were not classified, although their components Niobium and Tantalum were rather expensive... 

It has been used in pyrotechnic formulations, eg, in green stars Ba perchlorate 70.5, Mg powd 11.8, shellac 11.8 lycopodeum powd 5.9% (Ref 2). It is also a constituent of some expls (Ref 1), eg, in Leonard s smokeless powds... 

Pyrotechnics are specially formulated to produce a large volume of gases and a lot of energy. The special effects due to pyrotechnics are classified as... 

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