Effects of oxidizer structure on thermal and combustion behavior of Fe₂O₃/Zr thermite

Abstract Performance of MOF-derived micrometer porous Fe₂O₃ as the oxidizer in Zr-fuelled thermite is compared with commercial nano-sized Fe₂O₃ by characterizing thermal and combustion behavior of Fe₂O₃/Zr mixture via differential scanning calorimetry, optical emission measurement as well as composition and morphology analysis on condensed combustion products. Results show that thermal behaviors of Fe₂O₃/Zr with a slow heating rate have little difference regardless of the kind of Fe₂O₃. However, MOF-derived micrometer porous Fe₂O₃ show an obvious superiority in enhancing combustion of Fe₂O₃/Zr heated by a high rate. Combustion reactions of Fe₂O₃/Zr under high heating rates are probably rate-controlled by condensed reaction. The better performance of MOF-derived Fe₂O₃ is attributed to its larger contact area with Zr particle in that micrometer porous Fe₂O₃ particles are easily broken into primitive nano-sized particles, which effectively avoid the agglomeration of oxidizer. The MOF-derived Fe₂O₃ particles obtained at calcination temperature of 550 °C enable the best combustion performance of Fe₂O₃/Zr thermite. This should be because the crystallinity and porous structure of 550 °C-Fe₂O₃ are more favorable for the mass transfer process during high-rate combustion.