Effects of Gas Generation on Nano-Al Fueled Energetic Materials

The reactions of two nano-thermites aluminum (Al)with copper oxide (CuO) and Al with nickel oxide(NiO) are studied. These oxidizers were selectedbased on their predicted properties: similar flametemperatures but significantly opposing gasgeneration. Thermal equilibrium calculations predictthat Al+CuO will have a high gas output and theAl+NiO will produce little gas. Flame propagationrates and peak pressure measurements were taken forboth composites at various equivalence ratios usingan instrumented flame tube. Results show that theAl+CuO had approximately twice the propagation rateand peak pressure of the Al+NiO. A DSC/TGA was usedto determine the properties of the composites andreactants under low heating rates. Results indicatethat under slow heating both composites experiencealmost no mass loss. The results suggest that themelt-dispersion mechanism which is only engaged athigh heating rates leads to a dispersion of highvelocity molten Al clusters that promotes a pressurebuild-up by inducing a bulk movement of fluid. Thismechanism may promote convection without the need foradditional gas generation.