416603 Formation of Al-Cu Alloy during Al/CuO Thermite Combustion: Investigation on Off-Stoichiometry for Maximum Pressure Change

Wednesday, November 11, 2015: 5:33 PM
254A (Salt Palace Convention Center)
Kyuhyeon Lee1, Dahin Kim1, Whi Dong Kim1, Jaewon Shim1, Sangbum Bae1, Do Joong Shin1, Benjamin E. Treml2, Jichang Yoo3, Do-Heyoung Kim4, Tobias Hanrath2 and Doh C. Lee1, (1)Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea, (2)Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, (3)The 1st R&D Institute, Agency for Defense Development (ADD), Daejeon, South Korea, (4)School of Applied Chemical Engineering, Chonnam National University, GwangJu 500-757, South Korea

It is commonly observed that the highest pressurization rate is achieved where Al/CuO composites have slightly Al-rich condition compared to stoichiometric ratio. Although there were some effort for interpreting this phenomenon, proposed hypotheses cannot clearly explain the reason of phenomenon. Here, we examined off-stoichiometry of Al/CuO composites analyzing combustion product of the composites with various composition. X-ray diffraction analysis shows that there are several compounds including remained reactants, predicted products, especially, AlxCuy alloy. Electron microscopy analysis revealed that unreacted Al nanoparticles (NPs) are covered with Cu layer. The Cu layer on the surface of Al decreases reactivity of Al NPs and hinders combustion propagation. Analysis on heat and mass transfer shows produced Cu is gasified with generated heat during the reaction and gas-phase Cu travels from reaction sites to unreacted Al NPs before combustion wave reaches. From these analysis, we proposed combustion mechanism including formation of Cu layer on the Al NPs and AlxCuy alloy from intermetallic diffusion process.

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See more of this Session: Nano-Energetic Materials I
See more of this Group/Topical: Particle Technology Forum