New pyrotechnic smoke compositions, containing only environmentally benign materials, have been demonstrated to produce thick white smoke clouds upon combustion. These compositions use powdered boron carbide (B4C) as a pyrotechnic fuel, KNO3 as a pyrotechnic oxidizer, and KCl as a combustion temperature moderator. Small amounts of calcium stearate and polymeric binders may be added to moderate burning rate and for composition granulation. Prototype tests involving three preferred compositions were conducted in end- and core-burning grenade and canister configurations. Smoke release times ranged from 3.5 to 70 s for the grenades and from 8 to 100 s for the canisters. Notably, any desired smoke release time within these ranges may be obtained by fine adjustment to the calcium stearate content of the compositions and/or small changes to the device containers. Aerosolization efficiency and quantitative performance, as determined by smoke chamber measurements, remain consistent regardless of smoke release time. Impact, friction, and electrostatic discharge tests show that the compositions are insensitive to accidental ignition and are safe to handle.

Pyrotechnic smoke compositions for visual obscuration containing boron carbide, potassium nitrate, potassium chloride, and various lubricants are described. Only the waxy lubricants stearic acid and calcium stearate slowed the burning rate into a range suitable for end‐burning smoke grenades. For compositions pressed into steel cans, the addition of just 2 wt‐% calcium stearate was shown to reduce the burning rate from 0.50 cm s−1 to 0.09 cm s−1. In this system, potassium chloride serves as a diluent that reduces incandesence but also increases slag formation. Compositions containing potassium chloride in the 25–30 wt‐% range exhibited both acceptably low incandescense and slag formation upon burning, while also producing copious amounts of white smoke. These experimental compositions were loaded into full‐size grenade cans; field and smoke chamber testing revealed that they outperform the US Army’s in‐service M83 TA grenade both qualitatively and quantitatively. The photopic mass‐based figures of merit for experimental grenades KCl‐25, KCl‐30, and a production‐run M83 TA grenade were 2.51, 2.19, and 1.44 m2 g−1, respectively.

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