Ignition and Combustion Characterization of Ca(IO₃)₂‐based Pyrotechnic Composites with B, Al, and Ti

Abstract

This paper studies the reactive behavior of calcium iodate with Al, B and Ti fuel particles as a thermal and iodine release source for neutralization of biological materials that might be employed in weapons. Two different calcium iodate particle length scales (micron and submicron) with different fuel/oxidizer ratios were used to prepare the iodized nanopyrolants. The optimal ratio was found to be the one with equivalence ratio of 2.0 for all the three fuels. The reactivity of the pyrolants can be enhanced by dehydrating the Ca(IO3)2 or replacing the micron oxidizer particles with submicron particles. The thermal decomposition process of the pyrolants was investigated at low and high heating rate. The results show that B, Al and Ti nanoparticles can promote the decomposition of Ca(IO3)2, but the Ti nanoparticles are the most efficient, which lower temperature of the oxygen/iodine release from ∼660 °C to ∼400 °C. Thus, Ti/Ca(IO3)2 has the lowest ignition temperature of ∼400 °C. The various calcium iodate‐based pyrolants were shown to have a wide range of reactivity (1–4 orders of magnitude) and burn times (1–3 orders of magnitude), high flame temperature (1850–2800 K) and iodine loading capacity (∼20–60 wt.‐% of iodine), which makes it a promising class of biocidal energetic materials.

Silicon Nanoparticles for the Reactivity and Energetic Density Enhancement of Energetic-Biocidal Mesoparticle Composites

“…Figure b shows the snapshots of the thermite reaction recorded using a high-speed camera for 7.5 wt % Si/Al/Ca­(IO 3 ) 2 mesoparticles ignited by rapid heating on a Pt wire (heating rate ∼ 10 5 K/s). The mesoparticle composites show a violent reaction with an ignition temperature of ∼870 K. Previous studies have shown that metal iodate decomposition occurs prior to the thermite reaction, implying that combustion is limited by fuel release rather than by the oxidizer availability. , In order to probe the ignition mechanism and reaction products, the mesoparticle powders were coated on a Pt wire, followed by rapid, resistive heating to yield the ignition temperature and mass spectra of products from the thermite reaction. Figure b shows time-resolved mass spectra from the thermite reaction of a typical Al/Si/Ca­(IO 3 ) 2 mesoparticle composite under vacuum.…”

Organic and Inorganic Biocidal Energetic Materials for Agent Defeat Weapons: An Overview and Research Perspectives

“…In another study [112], the performances of Al and B were compared with those obtained using Ti in place of them. The ignition temperatures of Ti/Ca(IO 3 ) 2 thermites were considerably lower than Al/Ca(IO 3 ) 2 or B/Ca(IO 3 ) 2 ones and it was speculated that this difference was ascribable to the melting point of Al and to the diffusive resistance to interphase contact due to molten B 2 O 3 on B surface.…”