Mg-based reactive materials with high iodine concentration and biocidal characteristics of aerosolized Mg-based biocidal materials

This work is aimed to develop a stable Mg-based thermite with high iodine concentration and preliminarily set a method to test inactivation factor (IF) values of biocidal materials with proximity to the combat situation. First, Mg−I₂ composites were mechanochemically prepared and up to 10 wt% of iodine could be retained until the material heated to 265 °C. Then biocidal thermites were mechanochemically prepared using Mg−I₂ as a fuel and Ca(IO₃)₂ as an oxidizer. For Mg−I₂−Ca(IO₃)₂ thermites, apparent aging was observed in the material with a stoichiometric fuel-to-oxidizer ratio. In heated filament ignition tests, thermites had ignition temperatures of ~760 °C and ~820 °C at heating rates of 1800 K/s and 13000 K/s, respectively, and were slightly lower than that of pure Mg. Particle combustion test showed that the thermite with more fuel fraction burned faster. A setup based on the constant volume explosion experiment was established to test the inactivation effect of biocidal materials. Results showed that pure Mg had the best inactivation effect, and IF value doesn't have a clear correlation with max pressure achieved by explosions of biocidal materials. For results within the same max pressure range, IF value is proportional to the iodine concentration within the materials. Interestingly, for Mg, IF value was exponentially changed with max pressurization rate, this leads to the unexpected high IF value of Mg. This study shows excessive iodine or oxidizer could deactivate the biocidal material, and the heat release rate may play a crucial role in biocidal performance.