Friction Sensitivity of Azides

The lack of understanding of the mechanism of frictional initiation of azides limits the operational usefulness of the data obtained. There is little intrinsic merit in the isolated data for any explosive taken alone, but when the data are compared with those for other explosives for which there is also laboratory or industrial handling experience, friction sensitivity data can serve as guides to potential hazards. 

This is shown by the results obtained with the mallet friction test (Table IX). On a relative basis it can be seen that according to the mallet friction test the 

The emery-paper friction test is more discriminating (Tables XI and XII), the test revealing that dextrinated lead azide is less sensitive than Service, RD1333, and RD1343 lead azides. The values obtained for lead styphnate and barium styphnate suggest that they are as friction sensitive as dextrinated lead azide. 

Tests were also conducted to determine the effect of temperature on the friction sensitivity of the same materials [16]. None of the primary explosives revealed any marked temperature effect however, the fact that no large temperature effect was observed led Copp et al. to conclude that the action of the apparatus was mechanical rather than thermal. 

The sensitivity of primary explosives to mechanical action as distinct from the sensitivity to hot spots produced by mechanical action was proposed by Copp et al. to be associated with their relatively high lattice energies. 

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