The Characteristics and Microscopic Mechanism of Al-Mg Alloy Powder Explosion Inhibited by MCA and NaH2PO4

The fine dust can be produced and suspended in the air during Al-Mg alloy polishing process, which has a high risk of powder explosion. To investigate the inhibition effects of ammonium salts and phosphates, the suppressants of melamine cyanurate (MCA) and NaH2PO4 were selected for preventing the explosion of Al-Mg alloy powder. The results showed that the inhibition sensitivity of MCA on Al-Mg alloy powder is superior to NaH2PO4. According to the results of the functional groups on the explosion products, it showed that the effective inhibitory concentrations of MCA for Mg and Al components are 20 wt% and 40 wt%, while the corresponding inhibitory concentrations of NaH2PO4 are 50 wt% and more than 70 wt%, respective. The explosion suppression mechanism of MCA mainly included the effects of gas-phase inerting and chain reaction interruption, whereas the mechanism of NaH2PO4 was oxygen isolating by physical covering and chain reaction interruption. MCA and of NaH2PO4 can suppress the flame propagation by the consumption of the H and OH free radicals. The consumption rate of MCA on O radical was six times that of NaH2PO4. The inhibiting effect of MCA on Al-Mg alloy powder explosion was superior to NaH2PO4. The results provides theoretical basis for the prevention and control of explosion accidents on Al-Mg alloy powder.