Thermally active nano-aluminum particles with improved flowability prepared by adsorbing multi-component layer

The flowability of nano-aluminum (nAl) particles is poorly characterized or tailored but must be improved for their manufacturing or application of interest. In this work, a strategy was proposed to improve the fluidity of nAl particles and increase the active aluminum content of nAl particles to be higher than that of naturally passivated nAl with similar size by 14%. The main method was introducing the non-cohesive layers with high absorption ability to slow down the oxidizing gas diffusion on the nAl surface at room temperature. The gasses released by the adsorption layer combustion could inhibit the sintering of the produced nAl particles and thereby enhance the reaction efficiency at high temperatures, thus endowing nAl with thermal activity. Characterization and experimental results indicated that the multi-component adsorption layers were composed of amorphous carbon, thin oxide layer, and solvent molecules, which improved the flowability by weakening the cohesion between nAl particles. As a result, the produced nAl particles with improved flowability were evenly dispersed in the nAl/oxidizer mixture. This characteristic was conducive to the mass transfer and energy diffusion on the nAl surface during initial ignition and reaction propagation.