INFLUENCE OF FORMULATION PARAMETERS ON THE COMBUSTION AND OBSCURATION CHARACTERISTICS OF RED PHOSPHORUS/PYROGEL-BASED SMOKE COMPOSITIONS

Abstract

This study investigates the influence of Mg particle size and oxidizer type on the combustion and obscuration characteristics (including ignition temperature, heat of combustion, mass consumption rate, flame temperature, laser attenuation capability, and infrared screening efficiency) of red phosphorus (RP)/pyrogel-based smoke compositions. Samples were prepared using Mg powders with mean particle sizes ranging from 50.2 to 529.5 µm and four different oxidizers (NaNO₃, KNO₃, Ba(NO₃)₂, and Sr(NO₃)₂). The results showed that Mg particle size strongly affected the mass consumption rate (0.027–0.083 g.s^-1) and smoke-screen formation rate, while exerting negligible effects on ignition temperature, heat of combustion, and flame temperature. Among the oxidizers tested, NaNO₃ exhibited the most favorable smoke-generation performance, characterized by a higher mass consumption rate and the shortest time to achieve over 90% obscuration (18 s). The RP/pyrogel smoke screens exhibited effective infrared shielding in both the 3–5 µm and 8–12 µm bands, with screening times of approximately 30 s and 20 s, respectively. These findings provide a scientific basis for the selection and optimization of RP/pyrogel-based formulations for smoke-screen generation aimed at infrared shielding and laser energy attenuation.