Thermodynamic Modeling of Pyrotechnic Smoke Compositions

Some of the most effective visible obscurants for military applications are toxic or incendiary or present serious logistical complications. Sustainable alternatives are needed to mitigate the risks of human exposure and environmental contamination. The FactSage 6.4 software package was used to model the thermodynamics of pyrotechnic smoke compositions based on boron carbide, hexachloroethane, and phosphorus. The computational results are shown to be relevant in light of prior experimental observations. Boron phosphide is proposed as a benign source of phosphorus for next-generation pyrotechnic smoke compositions. The thermodynamics of the BP-KNO3 system have been studied computationally. The results indicate that certain stoichiometries should produce elemental phosphorus upon combustion. The properties of the BP-KNO3 system are examined considering the functional requirements of smoke munitions.