Silver azide crystal density

The heat capacity (C ) and heat conductivity (A) of crystals depend respectively on the vibrational density of states weighted by a Boltzmann s distribution factor and the anharmonic terms in the vibrational potential energy. C has been found to be in the range 0.100 to 0,117 cal./g./°C between 100—250 °C for crystals as widely varying in lattice geometry as mercuric fulminate, silver azide and lead azide 62). This is... 

The effect of crystal size on the critical hght energy and ignition delay was studied by Rogers and reported by Bowden and Yofle [32] for silver azide and by Roth [125] for lead azide. Each found that crystal size had no effect. Roth further reported that the density range 1.6-3.2 g/ml and the particle size range... 

More recently, Singh calculated ideal detonation velocities of single crystals and loose compacts of silver azide of different densities [127]. He assumed that silver and nitrogen at solid densities near 10.49 and 1.03 g/ml, respectively, obey the Mie-Griineisen EOS... 

Silver azide prepared by direct reaction of sodium azide and the soluble silver salt forms as a fine powder with a low bulk density. This is caused by its extremely low solubility and a tendency to nucleate profusely which results in extensive nucleations and very small crystals. Several processes have been developed for preparation of a product with a more suitable crystal structure. 

A method of preparing a reduced sensitivity SA introduced in USA is called the Costain process after Thomas Costain who improved the original procedure for RD 1336 developed in England in the ERDE laboratories shortly after World War 11 [96]. In the Costain process, aqueous solutions of silver nitrate and sodium azide are added to the dilute aqueous ammonia (or an aqueous solution of sodium azide is added to an aqueous solution of silver nitrate and ammonia). The reaction mixture is then heated and part of the ammonia is distilled from the solution. When the first silver azide precipitate appears, a small amount of acid (e.g., acetic acid) is added to induce crystal seeding and results in profuse nucleation ( shock crystallization ). The distillation of ammonia then continues and the precipitation of silver azide is total. Costain reported several improvements for his product, first of all bulk density 1.4 g cm [96]. Hirlinger and Bichay later reported a further improvement leading to a product with density 1.6 g cm [97] (vs. 1.0 g cm for original ERDE silver azide). Further, concentration and addition parameters are not as critical as for the ERDE process [96]. Not much has been published about the Costain process but some details have been published in [98]. 

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