Initiation and ignition of nano-aluminum in Teflon

Laser flash-heating;aluminum combustion;nanoparticles;laser ablation;fluorination;energetic materials;reactive materials

Conner, Rusty

关键词: Laser flash-heating;    aluminum combustion;    nanoparticles;    laser ablation;    fluorination;    energetic materials;    reactive materials;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/29703/Conner_Rusty.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

The combustion of nano-aluminum in Teflon was studied using time-resolved laserspectroscopy. This reactive material has a stored energy of ~21 kJ cm-3, nearly twice the energycontent of the best molecular explosives. Experiments investigated the fundamental combustionprocesses of initiation and ignition. Initiation occurs when the first bonds break in the material.This step usually requires energy, but allows the material to undergo the widespread release ofenergy, known as ignition. These experiments used pulsed laser absorption to heat Alnanoparticles to ~3000 K in ~100 picoseconds. This activated the materials, allowing reactionsto proceed. Initiation was studied by tracking changes in the vibrational band structure of Teflonusing transient absorption of a femtosecond mid-IR laser pulse. Ignition was studied byanalyzing the UV/visible burst of emission from flash-heated materials with an ultrafast streakcamera detector. After flash-heating, hot Al attacked the surrounding Teflon, consuming CFOgroups in ~50 ps. A confined Al plasma created by the laser registered the ~100 ps release ofenergy from the relaxation of nascent AlF, an elementary reaction product observed in theelectronic ground-state within ~200 ps.