Primary explosives densities

Primary explosives include mercury fulminate [Hg(ONC)2, melting point 160°C with explosion, density 4.2], lead azide [Pb(N3)2, density 4.0], basic lead styphnate (lead trinitroresorcinate), diazodinitrophenol, and tetrazine (a complex conjugated nitrogen compound, melting point 140 to 160°C with explosion). Most priming compositions consist of mixtures of primary explosives, fuels, and oxidants. 

While Region II can be compared with the hot-wire initiation of primary explosives or pyrotechnic compositions, the laser power densities in region IV also make it possible to directly shock initiate secondary explosives by laser irradiation. The laser power densities of Region IV are achieved by solid-state lasers with laser powers of at least 100 W. In contrast, laser diodes ( 1-10 W) only provide power densities which fall into the regions II and III. However, more powerful laser diodes have been gradually developed and therefore, laser diode initiators (LDI) have be-... 

Explosive Slow Neutron Irradiation of Primary Explosives (Ref 35) Metal Nitrogen Density Flux Total atoms nuclei reacting nuclei reacting (g/ml) (n/cm /sec) (per ml) (per sec) (per sec) Nuclear reaction... 

It is a primary explosive. It explodes violently upon thermal and mechanical shock. It requires lesser energy for initiation than lead azide and also fires with a shorter time delay. The heats of combustion and detonation are 1037 and 454 cal/g, respectively (i.e., 156 and 68 kcal/mol, respectively). The detonation velocity is 6.8 km/sec (at the crystal density 5.1 g/cm ). The pure compound explodes at 340°C (644°F) (Mellor 1967). The detonation can occur at much lower temperatures in an electric field when initiated by irradiation. Also, the presence of impurities can lower down the temperamre of detonation. Such impurities include oxides, sulfides, and selenides of copper and other metals. 

Neat solution-type liquid explosives are molecular mixture of all components with the best dispersion, mixing homogeneousness, and density consistency. Liquid explosives with suspended solid particles has the liquid primary explosive as the continuous media to form a sol-gel with the help of thickening agents, and their solid phase is suspended homogeneously in the system to form a mixture system. And the solid particles are surrounded by the liquid phase solution, and there are relatively ideal dispersion and uniformity of every component. Therefore, both of these two liquid explosive mixtures have sufficient explosion thermochemical reaction conditions, which makes almost aU chemical potentials of the explosive system can be released in the explosion reaction zone. And the calculation of liquid explosives with the dispersion of solid particles can be done according to the explosion property parameters of general explosive mixtures. 

Figure 9 illustrates the change in detonation velocity (km/sec) with change in density (g/cc) for some secondary explosives. Figure 10 illustrates the change in detonation velocity with change in density for some primary explosives. (Secondary and primary explosives will he covered later in the text.)... 

The test is conducted in the following manner 200 mg of hexogen are press-loaded at 1115 kp/cm in a polymethylmetacrylate (PMMA) holder. Above it, a primary explosive is filled in the state at which its initiating strength is to be tested freely poured or pressed to a desired density. The initiation of the primary explosive is performed by means of a safety fuse. If the depth of the dent produced after initiation in the steel witness plate of 70-90 Rockwell B hardness is greater than 0.76 mm, the complete detonation of hexogen is... 

It should be pointed out that the initiating strength of primary explosives depends on several factors, such as explosive purity, leading density, confinement conditions, etc. Thus, the results obtained by different testing methods are not directly comparable. 

Primary explosives are generally prepared in the form of crystalline or powdery material with low bulk densities and large specific surface. This form is hardly ever suitable for direct application and therefore it has to be further processed. For use in detonators they must be compacted by pressing to the detonator caps in a way that assures the best initiation properties. 

When higher pressures are used to achieve higher densities, a phenomenon called dead-pressing may occur, leading to a material which is hard to ignite and which, if ignited, only bums without detonation [1]. Pressing a primary explosive to a point where it loses its capability to detonate is therefore not desirable. 

The values in Fig. 2.1 show that the detonation velocity of both MF and LA increases with increasing density, as expected. In general, one would further expect that it is desirable to press explosives to densities as close to the theoretical maximum density (TMD) as possible. This is, however, not exactly the case for primary explosives in a detonator where it is more important to have good initiation efficiency rather than high detonation velocity. 

The graphs presented above clearly show that, in the case of primary explosives, optimal rather than high density should be used. All the more so as unnecessarily high pressures used for obtaining material of higher density are also more susceptible to detonations during compression. 

The compacting pressure is an important parameter not only for the primary but also for the secondary explosive as it influences the densities of both. The values tabulated in Table 2.1 refer to the amoimt of primary explosive causing detonation of PETN in 10 out of 10 trials [23]. It can be clearly seen that the xmcompressed PETN requires much lower amounts of practically all primary explosives than compressed PETN. The compression of the secondary charge may lead to such a... 

Dependence of detonation velocity on density is shown in Fig. 2.1. Mercury fulminate belongs to the group of primary explosives with a long predetonation zone. In other words, it means that it takes a long time, and uses significant amounts of charge, before the decomposition reaction accelerates from simple initial impulse to fully developed detonation (slow deflagration to detonation transition... 

TATNB is a powerful primary explosive. The dependence of detonation velocity on density is given in Table 4.20. 

Unsubstituted tetrazole (IH- or 2//-tetrazole sometimes referred as free tetrazole ) forms colorless crystals with density 1.632 g cm (X-ray) which melt at 155.5 °C without decomposition according to Fedoroff, Shefield, and Kaye s encyclopedia [1] or at 157-158 °C according to Bagal [2]. Tetrazole is easily soluble in water, ethanol, acetone, and acetic acid [2]. Heat of formation is 236 kJ mol [3]. Free tetrazole does not have the characteristics of a primary explosive. Tetrazole easily forms metallic salts owing to the acidic nature of its hydrogen atom [2]. A large number of its derivatives or derivative s salts do have explosive properties and many fall into the category of primary explosives. 

ColMSAT and PAC are known to have short DDT distances. The impact sensitivity of PAC determined by GOST-4545-88 (2 kg hammer, impact height 25 cm) is 16 %. The initiation efficiency for RDX is 0.4 g the calculated detonation velocity is 6.98 km s for density 1.82 g cm . This clearly indicates that the complex is a primary explosive (with relatively low initiation efficiency) but with sensitivity to mechanical stimuli comparable to secondary explosives [26]. 

The effect of the density of the primary explosive on the efficiency of detrmators is shown in Table 9.8. Performance of both complexes decreases with increasing loading pressure and density contrary to LA. This phenomenrMi is greater for the cupric complex. Performance of the ferrous complex is significantly higher at all... 

The silver acetylide-silver nitrate forms fine needle and cross crystals [28] as shown on Fig. 12.1 with density 5.36 g cm [6] or 5.369 (X-ray) [17]. The density is superior to MF and LA making Ag2C2-AgN03 a primary explosive with one of the highest known densities [29]. It decomposes by action of acids liberating acetylene ... 

This is not true, however, for some of the metalloorganic primary explosives. The high density of these compounds is caused by the presence of mercury or lead which does not add to energy content. 

Table 3.1 The effect of density on the velocity of detonation for the primary explosive, mercury fulminate and secondary explosive, nitroguanidine...

For pure primary secondary explosives (except for border-line HE such as Ammonium Nitrate or Ammonium Perchlorate) dcr decreases as p0 increases until p0 approaches very close single crystal density when dcr may increase drastically. Thus if we limit ourselves to p0 < 0.9pcrySt, increases in p0 (according to Eq 8) should result in a greater sensitivity to impact. This is quite the opposite of what is found for shock initiation and will be examined more closely later on. At a fixed density, dcr increases as p. increases (see A B, p 90). This increase is fairly pronounced at small p (<0.2 mm) but levels off becomes almost asymptotic at large p (>0.4mm, except for cast TNT or TNT with 1% paraffin oil). Thus an increase in p, as expected, leads to a decrease... 

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