Pyrotechnics boron

Amorphous boron is used in pyrotechnic flares to provide a distinctive green color, and in rockets as an igniter. 

Other typical pyrotechnic fuels include charcoal, sulfur, boron, siUcon, and synthetic polymers such as poly(vinyl alcohol) and poly(vinyl chloride). Extensive use has been made of natural products such as starches and gums, and the use of these materials continues to be substantial in the fireworks industry. MiUtary pyrotechnics have moved away from the use of natural products due to the inherent variabiUty in these materials depending on climatic conditions during the growth of the plants from which the compounds are derived. 

Elemental boron is used in very diverse industries from metallurgy (qv) to electronics. Other areas of appHcation include ceramics (qv), propulsion, pyrotechnics, and nuclear chemistry. Boron is nontoxic. Workplace hygienic practices, however, include a voiding the breathing of boron dust or fine powder. 

Boron mixed with an oxidizer is used as a pyrotechnic. This ordnance appHcation for missiles and rockets is predominandy military. However, boron is also used in air bags, placed in automobiles as safety devices, for initiating the sodium azide [26628-22-8] which fiHs the bag with nitrogen (13). Other boron compounds are also used in the air-bag pyrotechnic appHcation. 

For the particle size measurements of boron and barium dichromate, components of pyrotechnic delay compns, Freeman (Ref 46) evaluated the MSA. Particle Size Analyzer versus microscopy, gravitational liq sedimentation,... 

I.P. Borovinskaya, A New Class of Combustion Processes , Combustion Science Technology 10 (1975), 195—201. See also A.G. Merxhanov, Regularities and Mechanism of Combustion of Pyrotechnic Titanium Boron Mixtures , 4th Symposium, see Ref 148, See also V. Maslov et al, On Gasless Combustion Mechanism , FizikaGoreniaiVziyva 12, No 5... 

A pyrotechnic igniter consists of a basket of inorganic combustible materials, such as boron-potassium nitrate, which are usually in the form of pellets. This basket is also filled with a squib which provides a means of initiating the igniter. 

Calcium chromate, which contains 20% of boron is a composition used in pyrotechnics. 

Boron and silicon, whether they are on their own or combined, are used with sodium or potassium chromate to make pyrotechnic mixtures. 

Tulis, A. J. et al., Proc. 7th Symp. Explos. Pyrotechnics, 1971, 3(4), 1-12 Mixtures of boron and silver difluoride function as detonators when contacted with water. 

The mechanism of ignition and combustion of pyrotechnic mixtures of boron with potassium dichromate and/or sodium dichromate in presence or absence of silicon... 

Rogers, J. W., Proc. 8th Int. Pyrotech. Seminar, 1982, 556-573 Pyrotechnic properties of blends with 20% boron were studied [1], and the performance of several other blends has been assessed [2],... 

Uses. Amorphous boron is used as an addictive in pyrotechnic mixtures, solid rockets propellants, explosives, etc. Refractory metal borides are used as addic-tives to cemented carbides. High purity boron is used in electronics as a dopant to... 

Kuwahara, T., and Kubota, N., Role of Boron in Burning Rate Augmentation of AP Composite Propellants, Propellants, Explosives, Pyrotechnics, Vol. 14,1989, pp. 43-46. 

The most important application of boron is to make fibers or whiskers of single crystal or ceramic crystal. The addition of boron to metals, alloys, or other solids, imparts resistance to plastic flow, and thereby produces unusual strength in the material. Amorphous boron is used in rockets as an igniter, and in pyrotechnic flares to give green color. Many boron compounds, such as borax, boron hydrides, and boron hahdes, have important commercial applications (see individual compounds). 

Several readily-oxidized nonmetallic elements have found widespread use in the field of pyrotechnics. The requirements again are stability to air and moisture, good heat-per-gram output, and reasonable cost. Materials in common use include sulfur, boron, silicon, and phosphorus. Their properties are summarized in Table 3.5. 

McLain has proposed that the maximum in performance centered at approximately 15% boron by weight indicates that the principal pyrotechnic reaction for the BaCrO /B system is... 

Sometimes nanosized powders are also referred as ultrafine (UF) powders with an equivalent size of 10 to a few hundred nanometers. The commonly employed fuels for explosives, propellants and pyrotechnics are aluminum (Al), magnesium (Mg) and boron (B). However, the share in terms of quantity consumed is maximum for aluminum. 

Borates. A general term for salts of acids based on boron, such as metaboric HB02, perboric HBOs, tetra- or pyroboric H2B407, boric or orthoboric HjBOj and others. Props of various borates are given in Refs 1,3,5,6 7 and their uses in some pyrotechnic compns are listed in Ref 8 Following is the list of some borates". 

It was concluded, at that time, that replacement of Al by B in military expls showed no advantages over std expls. Boron has been used in the development of some gasless delay fuze compns and in pyrotechnic mixts for flares incendiary bombs (Ref 3). Werbel(Ref 2a) proposed Ba chromate/boron 95/5 mixt as delay compn 90/10 mixt as an igniter. Taschler Jones(Ref 5) have detd the e-lectrostatic sensitivity of barium chromate/boron compns. The performance of boron expls is described by Mader(Ref 4)... 

A mixture with boron incandesces on heating, and with silicon the reaction is vigorous. If aluminium is present the mixture explodes on heating (but the same is true if silicon is absent) [1]. The pyrotechnic reaction of boron and lead oxide mixtures has been studied by DSC [2]. 

The further new nitroethyl compounds based on boron esters are tris-(2-nitro-ethyl) borate and tris-(2,2,2-trinitroethyl) borate. Especially the trinitroethyl derivative is a suitable candidate for high energy density oxidizers and for smoke-free, green coloring agents in pyrotechnic compositions. Tris-(2-nitroethyl) borate and tris-(2,2,2-trinitroethyl) borate can be obtained from boron oxide with 2-nitroetha-nol and 2,2,2-trinitroethanol, respectively ... 

A breakthrough discovery was reported by Sabatini (ARDEC) in the area of green illuminants. Formulations without any heavy metal can be based on boron carbide (B4C, fuel) with a suitable oxidizer (e.g. Iboron carbide (B4C) in pyrotechnical compositions. It can be seen that flares with 100% boron carbide as fuel show longer burn times and higher luminous intensity than the control barium nitrate based flare (M125 Al) while the spectral (color) purity is slightly lower. 

Flammable by chemical reaction. A powerful oxidizer. Explosive reaction with hydrazine. Reacts violently or ignites with H2SO4 + acetone, hydroxylamine, ethylene glycol (above 100°C). Forms pyrotechnic mixtures with boron + silicon, iron (ignites at 1090°C), tungsten (ignites at 1700°C). Reacts with sulfuric acid to form the strong oxidant chromic acid. Used in... 

Boron is used as a reinforcing material for composites. It is used in the nuclear industry as a neutron absorber. Boron is used to harden metals and used as an oxygen scavenger for copper and other metals. Amorphous boron is used in pyrotechnic flares to produce a green color. Used as a catalyst in olefin polymerization and alcohol dehydration. The principal consumption pattern in the United States for boron is for the production of glass products with minor usage in the production of soaps and detergents. 

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