Extending Capabilities in Synthesis and Characterization of Energetic Materials
Abstract
Metal-based energetic materials (e.g., aluminum (Al) and boron (B)) can release a largeamount of heat, gas and light, due to their high volumetric and gravimetric energy densities. Forthis reason they have been widely studied and applied in; propellants, pyrotechnic signals, gasgeneration, agents for counter chemical and biological threats and weapon systems. All of whichare of great interest to the DoD. However, metal fuel particles suffer from high ignitiontemperature, slow energy release during oxidation reactions and incomplete combustion, resultingin lower than expected performance. Therefore, it is of long-term interest to the DoD to continueto understand the fundamentals of metal ignition and combustion properties and to developmethods to enhance these properties. Zheng~s group has worked on metal-based energeticmaterials for over a decade with the support of the DoD and is experienced in the synthesis andcharacterization of advanced energetic materials. Many exciting opportunities have emerged inenergetic materials over the past decade due to the rapid advancement in synthesis andcharacterizations of materials. However, we cannot take full advantage of such advancements dueto our current laboratory facilities. Hence, we propose to upgrade our capabilities to extend thecapabilities in material synthesis, environment of operation, measurement of transient temperatureand chemical species profiles.We propose to purchase and establish two complementary equipment systems to supporton-going DoD funded and proposed research in metal-related energetic materials. The first systemincludes a cryogenic ball mill and a glove box, enabling preparation of a suite of energeticmaterials such as: (1) energetic composites mixed at nanoscale (e.g., metal-metal, metal-polymer,metal-oxidizer, metal-porous Si, and metal-graphene); (2) surface-functionalized metals withoutsurface oxide layers (e.g., fluorinated-Al and graphene-wrapped Al). The second proposed systemincludes a CO2 laser as a quantitative ignition source, a spectrometer for species measurement anda high speed infrared camera for time-resolved temperature field measurement. The second systemwill enable quantification of important energetic material properties including: (1) minimalignition energy, (2) time-resolved spatial temperature profiles, and (3) time-resolved speciesemission profiles. These capabilities will elucidate ignition behaviors, combustion efficiency andcombustion chemistry of various energetic materials. The two systems will complement ourexisting equipment: a high speed camera for imaging; a constant-volume vessel for time-resolvedpressure profiles; a bomb calorimeter for combustion efficiency characterization and;simultaneous thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC) forslow heating reaction characterization.The proposed instrumentation will enhance our current ONR supported research, studyingthe effect of porous Si addition on Al micron particle ignition and combustion, and our proposedresearch, to study the interface chemistry between B and hydroxyl-terminated polybutadiene(HTPB) on their combustion properties. Finally, the upgrade of synthesis and characterizationcapabilities of energetic materials will provide unique educational opportunities for graduatestudents, undergraduates and summer high school intern students in the areas of materials science,combustion and propulsion.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jun 13, 2019
- Source ID
- N000141912428
Entities
People
- Xiaolin Zheng
Organizations
- Office of Naval Research
- Stanford University
- United States Navy