Silver ferrite: a superior oxidizer for thermite-driven biocidal nanoenergetic materials

Abstract

Silver-containing oxidizers are of interest as biocidal components in energetic application such as thermites due to their biocidal agent delivery. In this study, AgFeO₂, was evaluated as an oxidizer in aluminum-based thermite system. This novel oxidizer AgFeO₂ particles were prepared via a wet-chemistry method and its structure, morphologies and thermal behavior were investigated using X-ray diffraction, scanning electron microscopy, thermogravimetric analysis and differential scanning calorimetry, and time-resolved temperature-jump time-of-flight mass spectrometry. The results indicate the decomposition pathways of AgFeO₂ vary with heating rates from a two-step at low heating rate to a single step at high heating rate. Ignition of Al/AgFeO₂ occurs at a temperature just above the oxygen release temperature that is very similar to Al/Fe₂O₃ and Al/CuO. However, with a pressurization rate three times of Al/CuO, Al/AgFeO₂ yields a comparable result as to Al/hollow-CuO or Al/KClO₄/CuO, with a simpler preparation method. The post combustion products demonstrated that the Al/AgFeO₂ thermite reaction produces a fine dispersion of elemental nanosized silver particles which coats the larger alumina particles and is thus bioavailable.