Effect of ammonium perchlorate particle size on its detonation characteristics when sensitized with small amounts of nitroguanidine

Abstract

Sympathetic detonation has already been achieved in ammonium perchlorate by adding small amounts of nitroguanidine. Although it appeared that the ammonium perchlorate was detonating at the ideal detonation velocity of the nitroguanidine additive, the effects of confinement, charge diameter, and ammonium perchlorate particle size were not assessed. The effects of confinement and charge diameter were subsequently investigated. In all these studies, however, the particle size of the ammonium perchlorate remained unchanged--nominally 200 micron Class C mil spec ammonium perchlorate. The present effort investigated the effect of variable ammonium perchlorate particle size upon the detonation characteristics of a typical ammonium perchlorate composite system: one sensitized with 5 percent nitroguanidine. Three particle size ranges--designated coarse (149 to 500 micron), medium (44 to 149 micron), and fine (0 to 44 micron)--were investigated. Screen-sieve separation was used. Although the results did confirm a general increase of detonation velocity with a decrease in ammonium perchlorate particle size, some anomalous behavior was also identified. A more comprehensive study will be needed to elucidate the effects of particle size or, more generally, the particle size distribution.