SHOCK INITIATION OF LOW-DENSITY PRESSINGS OF AMMONIUM PERCHLORATE

Abstract : Iniation and detonation behavior of 13-micron ammonium perchlorate was studied at loading density 1.00 g/cu. cm. Steady detonation velocities were determined experimentally at three diameters and extrapolated to 3.75 = 0.15 mm/ micro sec at infinite diameter. Calculations with the BKW equation of state gave 4.25 mm/micro sec--as good agreement as could be expected for a low-energy chlorine--containing explosive. By introducing 24-kbar flat-topped plane shocks into pellets of various lengths, it was determined that steady full-strength detonation was reached after about 15 mm travel. The growth of pressure in the accelerating wave was followed approximately by means of free-surface measurements on thin Plexiglas at the top surfaces of the pellets, and these measurements indicated the pressure to be 55 = 10 kbar in the full-strength wave. Reducing the air pressure in the pressings to 5 microns left the build-up to detonation unaffected. The position of the shock Hugoniot for the pressings relative to the Hugoniot of the solid crystal is discussed in terms of heat production during collapse and possible reaction processes. (Author)