Primary explosives silver azide

Primary explosives differ from secondary explosives in that they undergo a rapid transition from burning to detonation and have the ability to transmit the detonation to less sensitive (but more powerful) secondary explosives. Primary explosives have high degrees of sensitivity to initiation through shock, friction, electric spark, or high temperature, and explode whether confined or unconfined. Some widely used primary explosives include lead azide, silver azide, tetrazene, lead styphnate, mercury fulminate, and diazodinitrophenol. Nuclear weapon applications normally limit the use of primary explosives to lead azide and lead styphnate. 

Silver azide (AgN3) is a white-colored crystalline explosive. It requires less energy for initiation than lead azide, and fires with a shorter time delay. This primary explosive decomposes under the influence of ultraviolet radiation. If the ultraviolet... 

It is a primary explosive and is slightly more sensitive to impact than Lead and Silver Azides. It would require 0.25g of this explosive to detonate lg of TNT... 

Figure A. 147 Silver azide primary high explosive.

Examination of nitration acids 167—191 — Examination of finished products propellants, secondary expls and primary expls 192 — Examination of individual expls solid TNT, liquid TNT, Hexogen (RDX), Hexotol (Cyclotol), Hexotonal (RDX/TNT/A1, Torpex), Penthrite (PETN), Bofors Plastic Explosive (BPE), Bonocord, Tetryl, Lead Azide, Lead Styphnate, Mercury Fulminate, Silver Azide and Tetracene]... 

The explosive properties of sodium, calcium, strontium and barium azides have been investigated at the Chemisch-Technische Reichsanstalt [135]. These azides differ markedly from lead, silver and cupric azides in that they show none of the properties of primary explosives. All three may be ignited by a spark, a glowing wire or the flame of blackpowder. Calcium azide bums most rapidly and has distinctly marked explosive properties. Larger quantities of it may explode when ignited in a closed tin, while strontium and barium merely bum violently. Calcium azide detonates under the influence of a detonating cap. The sodium azide does not decompose in these conditions. The other azides show weak decomposition under the influence of a standard (No. 3) detonator. Their most important properties are tabulated below. 

Lead and silver azides are widely used as initiating, or primary explosives because they can be readily detonated by heat, impact, or friction. As such, these materials, particularly lead azide, arc used in blasting caps, percussion caps, and delay initiating devices. The function of the azides is similar to that of mercury fulminate or silver fulminate. 

Primary Explosives Mercury fulminate Lead azide Silver azide Lead styphnate Mannitol hexanitrate (Nitromannite) Diazodinitrophenol Tetrazene... 

Pb(N3)2 is better known than almost any inorganic azide in fact, the number of publications written on it is surpassed only by sodium azide and HN3. This is undoubtedly because lead azide has been used for nearly 60 years as an effective, if sometimes problematic, primary explosive. It is not the first azide to be considered for military use the feasibility of silver azide was explored in Germany as early as 1904. In 1911, lead azide was suggested as a military explosive by Wohler [224], and being technically and economically superior [275] to mercury fulminate, has gradually replaced the latter. 

M. M. Jones et al [123] surveyed several EOSs with respect to their potential usefulness in C-J calculations on dense primary explosives (including, of course, the heavy-metal azides). However, calculations were reported only for silver azide and lead azide. Four EOSs were employed in the calculations and represent major categories of equations which show promise for future applications. 

Impact sensitivity of lead aiul silver azides depends on the size of crystals or pellet thickness. The larger the crystals, the more sensitive they are. This and other problems related to the initiation of primary explosives are dfscussed by Bowden and YolTe [125] and extensively reviewed by Chaudliri and rielci [3 (Vol. 1, p. 383)]. 

For primary explosives the power or the energy in a nanosecond laser pulse is sufficient to initiate these explosives. For example, lead azide or silver azide require only a few mJ s in a nanosecond laser pulse, while most nanosecond pulse lasers deliver at least several tens... 

Apart from the already mentioned lead azide and mercury fulmiate, the classic examples of primary explosives include lead styphnate (LS), silver azide (SA), dinol (DDNP), and tetrazene (GNGT). Primary explosives (individual components) are often mixed and used in the form of compositions rather than as single component energetic materials. Mixtures may consist of either individual primary explosives (astryl-MF/SA [2]) or primary explosives plus some nonexplosive additive (LA/LS/ dextrine or ASA composition— LA/LS/Al). 

Fig. 2.2 Initiation efficiencies of some primary explosives for TNT (previously unused acronyms SF silver fulminate, SA silver azide, TATP triacetone triperoxide) [4, 5, 17—22]...

Some primary explosives are reported to have extreme sensitivity. SF and SA are two such substances. Extreme sensitivity of SF is reported in [33], very high sensitivity (approximately 2-3 times higher than that of LA depending on the testing surface) is reported for SA [55]. Such statements must be carefully considered and evaluation based on solid data. Extreme sensitivity of SA is, for example, commonly found in older sources and could be the result of the method of preparation. In the early days, SA was prepared by direct precipitation of aqueous solutions of sodium azide and the silver salt and such a method of preparation could have led to a more sensitive product. Today s industrial SA (product of BAE Systems) is reported to have sensitivity lower than that of LA (determined by emery Motion test) [56]. 

Silver fulminate is considered as an extremely dangerous primary explosive to handle due to its high sensitivity, particularly to electric discharge and friction. It is more sensitive than MF with respect to both of these initiation stimuli. The sensitivity to electric discharge is extreme, particularly when it is dry [92]. The sensitivity of silver fulminate depends on its crystal form the amorphous form is less sensitive to impact than the crystalline form. However, since it is practically impossible to produce purely amorphous material without any crystals the whole mass might be nearly as sensitive as the crystalline form itself [29]. Taylor and Buxton published preparation of SF in form of fine crystals with an impact sensitivity significantly lower than MF (no explosion from 32.7 cm for 1/2 kg hammer vs. only 12.7 cm for MF) approaching values typical for lead azide [93]. Comparison of impact sensitivity of SF with other common primary explosives is shown in Fig. 2.15. 

Silver azide is generally considered to be highly sensitive to friction and much more than other common primary explosives including LA [21, 84] and, just as with impact, friction sensitivity depends considerably on its crystalline form [65]. The values reported by Millar [81] for two specific kinds of LA (RD 1343) and SA (RD 1374) are presented in Table 4.6. It follows from the results that the sensitivity of at least some commercially produced SA is lower than that of LA. Sensitivity of SA to electrical discharge is higher than that of LA (Table 4.6), while sensitivity to flame is about the same as that of mercury fulminate [6, 21]. 

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