Engineered Porosity-Induced Burn Rate Enhancement in Dense Al/CuO Nanothermites

This work investigates the combustion of porous Al/CuO thermites, that is, nanolaminates fabricated with various densities micron-sized air-filled pores in range 0–20 vol %. High-speed videography and pyrometry high-temperature propagating flame were used to analyze effect porosity on propagation velocity. Incorporating results a faster burn rate (burn enhancement 18% for pore loading 20 %) while temperature remains same. Microscopic observations front show hotspots around each upstream but no advection. Conduction dominant heat transfer mechanism dense thermite configuration (80% theoretical maximum density) causes when are embedded into nanolaminate found be convection trapped air inside upon heating together possible modification reaction chemistry leading lowering ignition threshold pores. Indeed, this hot gaseous O2 species diffuse react solid Al inner wall form Al2O3. gas-phase mediated occurs at lower than diffusion-based aluminum cations oxide anions across alumina shell as fully nanolaminates. The critical size beyond which their beneficial disappears is difficult estimate, study showed 100 × ?m2 have almost an average increase only ?4% compared part.