Advanced Boron Carbide-Based Visual Obscurants for Military Smoke Grenades

摘要

Military visible obscuration compositions (obscurants, smokes) are characterized by a hazard/ performance trade-off. New compositions with improved performance, but containing only benign materials, are needed for the next generation of U.S. Army smoke munitions. Advanced boron carbide-based smoke compositions have been developed to address this need. These experimental compositions contain B4C/KNO3 as a pyrotechnic fuel/oxidizer pair, KCl as a diluent, and calcium stearate as a burning rate modifier. Both the B4C particle size and the amount of calcium stearate may be used to control grenade burning times over a wide range (24-100 s demonstrated in the end-burning configuration). The dustiness of these dry compositions may be reduced by granulating them with a variety of polymeric binders. Granulation with polyvinyl acetate reduced dust and did not adversely affect composition burning rate or visible obscuration performance. In field and smoke chamber tests, prototype smoke grenades outperformed the U.S. Army M83 TA grenade by a wide margin. The best prototypes are functionally equivalent to nearly two M83 TA smoke grenades and are candidates for the eventual improvement/replacement of this grenade.