Microsphere Composites of Nano-Al and Nanothermite: An Approach to Better Utilization of Nanomaterials.

摘要

Nanometallic fuels suffer from processing challenges that have significantly retarded their utility, primarily because their very high surface area/small particle size increases the viscosity of the polymer binder and oxidizer mix, such that high mass fractions of fuel cannot be formulated. The other concern is that they lose surface area rapidly, on a time-scale commensurate with combustion. We employ electrospray as a means to create a gel within a droplet by evaporation induced rapid aggregation of aluminum and oxidizer nanoparticles containing a small mass fraction of an energetic binder. We find that the average size of the microparticles can be systematically changed from 2 microns to 16 microns. The combustion behavior is found to be very different from either nanoaluminum or micron aluminum and their corresponding thermite mixtures. The material which is super-micron sized has surface area consistent with the nanoparticle comprising it and the binder serves to act as a gas generator to minimize sintering.