Preparation and performance evaluation of Al–Mg alloy powder capsules

Aluminum–magnesium (Al–Mg) alloy powder can significantly enhance the loading density of mixed explosive charges and increase the energy release rate during detonation reactions. However, Al–Mg alloy powder is prone to oxidation and agglomeration in air, and the resulting surface oxide layer can substantially reduce its energy release capacity. To address this issue, a method is proposed to modify the surface of Al–Mg alloy powder using a silane coupling agent. This process involves coating the Al–Mg alloy powder with a Bis-(3-(triethoxysilyl)propyl) tetrasulfide (BTSPS) film, thereby forming highly stable Al–Mg alloy capsules. First, a study was conducted to optimize the preparation process of the BTSPS film. Subsequently, phase analysis methods were employed to evaluate the extent to which the BTSPS film improves the oxidation resistance of the Al–Mg alloy powder. Finally, comparative performance validation tests were conducted on explosives containing Al–Mg alloy powder and those containing Al–Mg alloy capsules. The experimental results demonstrate that the detonation velocity of the explosives containing Al–Mg alloy capsules increased by 0.4%, the detonation heat increased by 4%, the impact sensitivity decreased by 12%, and the friction sensitivity decreased by 24%.