Pre-stressing micron-scale aluminum core-shell particles to improve reactivity

Area of Science:

• Materials Science
• Chemical Engineering
• Energetic Materials

Background:

• Increasing aluminum (Al) particle reactivity for energetic applications typically involves reducing particle size to the nanoscale.
• Aluminum nanoparticles are significantly more expensive and present safety/environmental concerns compared to micron-scale particles.

Purpose of the Study:

• To enhance the reactivity of micron-scale aluminum particles as a cost-effective alternative to nanoparticles.
• To investigate the synthesis of pre-stressed core-shell structures in aluminum particles to improve their energetic performance.

Main Methods:

• Synthesized pre-stressed core-shell structures in micron-scale aluminum particles through annealing and quenching processes.
• Induce compressive stresses in the alumina passivation shell surrounding the aluminum core.
• Utilized the melt-dispersion mechanism (MDM) theory to guide thermal treatment design for high heating rate reactions.

Main Results:

• Experimental flame propagation rates for aluminum particles treated with nanoscale copper oxide (CuO) showed quantitative agreement with MDM predictions.
• The optimized thermal treatment increased flame propagation rate by 36%.
• Achieved 68% of the flame propagation rate of the best-performing aluminum nanoparticles.

Conclusions:

• Pre-stressed core-shell structures effectively improve the reactivity of micron-scale aluminum particles.
• This approach offers a viable, cost-effective strategy to enhance energetic material performance, bridging the gap between micron and nano-scale aluminum.
• The findings validate the melt-dispersion mechanism (MDM) as a predictive tool for optimizing thermal treatments of aluminum particles.