Boron mixtures

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... 

The increase in the deton vel of TNT-combustible metal (such as colloidal boron) mixtures at chge diams greater than 40mm showed that metals (in particular boron) can bum-up in the deton wave of condensed expls with the liberation of an additional amt of heat which leads to the growth of... 

Increase the system pressure, H2 gas flow, and the microwave power till the desired setting value is gradually attained. At pressure of 115 Torr, H2 of 532 seem, and power of 5000 W, introduce the carbon and boron mixture by bubbling it with H2 gas of 10 seem. The growth conditions are given in Table 14.1. 

Boron. Mixtures of boron and potassium dichromate with or without silicon may ignite.2... 

Boron. Mixtures in the presence or absence of silicon may ignite.3... 

Fig. 35. Combustion temperature and velocity of hathium-boron mixture as a function of dilution by final product (Adapted from Andreev et aL, 1980).

Tantalum-carbon, tantalum-boron, and niobium-boron mixtures may be classified as so-called solid flame systems, where T c is lower than the melting points of both reactants and products. Consequently, the sizes of reactant particles are not expected to change in the combustion wave. The dependence of U on the average metal particle size for these systems is presented in Fig. 47. 

Andreev, V. A., Mal tsev, N. M., and Seleznev, V. A., Study of the combustion of hafnium-boron mixtures by optical pyrometry. Combust. Explos. Shock Waves, 16,374 (1980). 

Table XII. Pulsed Reactor Irradiation of Lead Azide/Boron Mixtures 69]...

The Li ion and a-particle are stopped in the lead azide-boron mixture, converting their kinetic energy of 2.78 MeV to thermal energy. 

The green colour comes from BO2 band spectrum. The boron mixture is used as an ignition composition in place of thermit, and the difference between the two lies in that the former ignites other compositions with its high temperature flame but the latter mainly with its high temperature liquid cinder. Amorphous boron is very expensive commercially, but it is very useful when the ignition surface of a composition cannot be pasted with thermit as in the case of a rocket propellant which must start without a delay. The boron mixture ignites very well from a relatively weak heat source such as a black powder flame. 

Figure 1. Backscattered electron (BSE) images of the morphology of powders processed under shearing mode by reactive mechanical alloying under hydrogen, a) 2Mg-Co mixture milled for 30h using WD=10 mm and BPWR=10 1 and b) Mg-2B (crystalline (c) boron) mixture milled for 5h using WD=5 mm and BPWR=44 1. RPM=60 applied during milling.

With allowances for the actual metal content of zirconium (a small correction is also necessary for the hafnium content of about 2 /2%) and postulation of barium zirconate formation (see Table 27), reasonable accord between calculated and measured caloric output is established. However, the situation is more complex with boron mixtures where one encounters increase of heat output with increase of the percentage of boron in the mixtures much beyond the amounts of Equation (la). Thus, even with the reasonable assumption of secondary barium borate formation, the stoichiometry and heat output of the mixtures with more than about 10% of technical boron theoretical 8%) is obscure. Chromium boride formation may be a fector. 

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