Ignition and Combustion Characteristics of Atomized Al-Mg Alloy Particles with Different Compositions

The utilization of Al-Mg alloy, which combines the advantages of aluminum and magnesium, shows promise in solid propellant applications. This study investigates the slow oxidation, ignition, and combustion characteristics of atomized Al-Mg alloy particles with various compositions. The thermogravimetry (TG)/differential thermal analysis (DTA) and a single-particle ignition experimental system are employed for analysis. Simultaneous measurements of particle size (D), ignition delay time (t(i)), and combustion time (t(c)) are captured using a two-camera system. Results demonstrate that the slow oxidation of alloy powders in an oxygen environment can be classified into three stages. The initial oxidation occurs at approximately 826 K, where both magnesium and part of aluminum are oxidized (Stage II). The remaining oxidation takes place at around 1100 K (Stage III). The concentration of magnesium in the alloy particle within the range of 10-20 at.% does not significantly affect the ignition delay time under all experimental conditions. However, alloy particles with a low magnesium content of 10 at.% exhibit relatively short combustion times at high-temperature experimental conditions. A higher effective oxidizer mole fraction in the oxidizing environment leads to a longer ignition delay time but a shorter combustion time. Furthermore, combustion time decreases with an increase in ambient temperature in most experimental conditions. The average combustion temperatures, determined using the two-color thermometry method, are 2204.7 K for Al50Mg50 particles, 2225.6 K for Al60Mg40 particles, and 2733.6 K for Al90Mg10 particles.