Oxidation and ignition of a heterogeneous Al-Zn alloy powder metallic fuel

In this work, a heterogeneous Al-Zn alloy was developed as a metallic fuel to overcome the ignition time delay and low combustion rate of Al energetic materials. Al-Zn alloy powders were prepared by a high-speed centrifugal atomization method, which distributed Al and Zn uniformly on the surfaces and insides of the resulting spherical particles. The temperature at which the particles’ oxide shells cracked was lower and the laser ignition delay was 35 ms shorter for the Al-Zn alloy than for Al, based on TG-DSC results. The reason is that the low-temperature vaporization of Zn exacerbated the breakage of Al₂O₃ shells, and the heat accumulated during the vapour-phase combustion of Zn heated the particle to the reaction temperature of Al. Therefore, the addition of Zn enhances the combustion behaviour of Al by accelerating the rate of heat release.