Speaker: Dr. Edward L. Dreizin, Distinguished Professor, Chemical & Materials Engineering, New Jersey Institute of Technology

https://people.njit.edu/profile/dreyzin/

Title of Talk: Changing Morphology And Combustion Properties Of Metal Fuels Using Emulsion-Assisted Milling

Abstract:Aluminum and boron powders are attractive metal fuels used in propellants, explosives, and pyrotechnics. They have gravimetric and volumetric heats of combustion exceeding those of hydrocarbon fuels. Thus, a smaller charge can release more energy. In many situations, however, the rate of energy release by metal fuels is slower than desired. This motivates a broad range of studies aimed at modifying or improving the metal fuels with the goal of accelerating the energy release while maintaining the high energy density. Most of the work focused on designing alloys or composites combining the primary fuel, aluminum or boron, with certain additives. The effect of the morphology of the fuel powder particles on their reactivity is much less studied. Recently, a new material processing method, Emulsion-Assisted Milling, was developed at NJIT. It yields powders with spherical particle shapes and narrow size distributions. Each particle is an aggregate of densely packed submicron particles. The method is material-agnostic and can prepare powders comprising any number of finely mixed starting materials. Here, powders of elemental aluminum and boron are prepared, and their combustion characteristics are compared vs. similarly sized powders prepared by conventional methods. The experiment is focused on the characteristics of combustion of individual particles. It is found that the powders with distinct initial morphology burn differently. This is surprising because the particles burn at temperatures exceeding the melting points of the respective elements. It is also interesting because a new way of tuning metal combustion is discovered.