Influence of the amount of a $\mathrm{Fe}_2\mathrm{O}_3$ modifier on the oxidation rate of ASD-4 micron-sized powder

The effect of the modification of ASD-4 micron-sized aluminum powder with iron oxide on its oxidation in air is investigated. The modification consisted of coating the surface of metal particles with gel based on $\mathrm{Fe}(\mathrm{OH})(\mathrm{HCOO})_2$ and ethylene glycol monomethyl ether, $\mathrm{CH}_3\mathrm{OC}_2\mathrm{H}_4\mathrm{OH}$, followed by heat treatment in air. It was found that the presence of iron oxide generally has a positive effect on the dynamics of oxidation ASD-4 powder when heated in air. The oxidation rate of modified powders increases with increasing content of iron oxide in them. X-ray diffraction analysis using a synchrotron radiation source under heating to $1000^\circ$C showed that the samples contained only the main phases $\gamma$-$\mathrm{Al}_2\mathrm{O}_3$ and $\alpha$-$\mathrm{Al}_2\mathrm{O}_3$, $\gamma$-$\mathrm{Fe}_2\mathrm{O}_3$ and $\alpha$-$\mathrm{Fe}_2\mathrm{O}_3$, and other iron oxides or intermetallic compounds were not found. At a mass concentration of $10\%\mathrm{Fe}$, an earlier appearance of the phase $\alpha$-$\mathrm{Al}_2\mathrm{O}_3$ is observed and the exothermic peak of maximum heat release is shifted to lower temperatures ($893^\circ$C) compared to the unmodified ASD-4 powder ($1045^\circ$C).