Study of the Combustion Mechanism of Zn/KMnO4 Pyrotechnic Composition

This work aims to investigate the combustion mechanism for a pyrotechnic delay composition (PDC), consisting of zinc powder as a fuel and KMnO4 as an oxidising agent. For this purpose, the compositions were thermally conditioned at several set temperatures, chosen based on our previous work. Tests were also performed for post-combustion residues obtained via combustion of the PDCs in a manometric bomb. The samples were examined by scanning electron microscopy (SEM), Raman spectroscopy and X-ray diffractometry (XRD). Furthermore, the obtained results were correlated with previous studies by the authors and compared with data available in the literature. On the basis of tests carried out for thermally conditioned samples, a combustion mechanism was determined for Zn/KMnO4 as a function of temperature. The results show that the combustion process dynamics are independent of equilibrium ratio and limited mainly by diffusion of liquid fuel into the solid oxidising agent. Moreover, it has been revealed that Raman spectroscopy can be effectively used to determine combustion mechanisms for pyrotechnic compositions.

Automated summary

This study investigates the combustion mechanism of a pyrotechnic delay composition (PDC) containing zinc powder as fuel and KMnO4 as oxidising agent. The PDC compositions were thermally conditioned at different temperatures and post-combustion residues were analyzed. The results, obtained through SEM, Raman spectroscopy, and XRD, were compared with previous studies and literature data. Based on the tests, a combustion mechanism for Zn/KMnO4 was determined, showing that the combustion process is independent of equilibrium ratio and mainly limited by the diffusion of liquid fuel into the solid oxidising agent. Moreover, Raman spectroscopy was found to be effective in determining combustion mechanisms for pyrotechnic compositions.