Boron-based reactive materials with high concentrations of iodine as a biocidal additive

Metal-based iodine-bearing reactive materials are of interest as additives to energetic formulations aimed to defeat biological weapons of mass destruction. This work was aimed to develop a material including a boron-based thermite with the maximized iodine concentration. The thermite was prepared mechanochemically, and Ca(IO₃)₂ served as an oxidizer. First, a B·I₂ composite powder was prepared starting with 40 wt% of iodine. This composite retains up to 30% of iodine, which is released in three steps upon heating. The main iodine loss occurs at temperatures exceeding 673 K (400 °C). The binary B·I₂ powder was used as a starting material to prepare the final thermite with the total concentration of iodine of 57.6 wt%. The thermite comprises loose agglomerates with particle sizes in the range of 1–10 µm, with submicron boron-iodine particles embedded in Ca(IO₃)₂. Combustion tests of the ternary composite thermite powder in an air-acetylene flame showed the flame temperatures close to 2050 K, and solid residue in the form of fine oxidized spheres with boron and calcium oxides mixed homogeneously. A correlation between particle sizes and their burn times is reported as well.