Micro- and Nanoscale Energetic Materials as Effective Heat Energy Sources for Enhanced Gas Generators

In this study, we systematically investigated the effect of micro- and nanoscale energetic materials in formulations of aluminum microparticles (Al MPs; heat source)/aluminum nanoparticles (Al NPs; heat source)/copper oxide nanoparticles (CuO NPs; oxidizer) on the combustion and gas-generating properties of sodium azide microparticles (NaN3 MPs; gas generating agent) for potential applications in gas generators. The burn rate of the NaN3 MP/CuO NP composite powder was only similar to 0.3 m/s. However, the addition of Al MPs and Al NPs to the NaN3 MP/CuO NP matrix caused the rates to reach similar to 1.5 and similar to 5.3 m/s, respectively. In addition, the N-2 gas volume flow rate generated by the ignition of the NaN3 MP/CuO NP composite powder was only similar to 0.6 L/s, which was significantly increased to similar to 1.4 and similar to 3.9 L/s by adding Al MPs and Al NPs, respectively, to the NaN3 MP/CuO NP composite powder. This suggested that the highly reactive Al MPs and NPs, with the assistance of CuO NPs, were effective heat-generating sources enabling the complete thermal decomposition of NaN3 MPs upon ignition. Al NPs were more effective than Al MPs in the gas generators because of the increased reactivity induced by the reduced particle size. Finally, we successfully demonstrated that a homemade airbag with a specific volume of similar to 140 mL could be rapidly and fully inflated by the thermal activation of nanoscale energetic material-added gas-generating agents (i.e., NaN3 MP/Al NP/CuO NP composites) within the standard time of similar to 50 ms for airbag inflation.