Aluminum micro- and nanoparticles have garnered interest from researchers as solid-state fuel in heterogenous energetic composites due to their high energy density, low cost, and general abundance. To react, aluminum particles must undergo an oxidation reaction with nearby oxidizers to release heat and produce gaseous products. This process is governed by diffusion of aluminum and oxygen through the passivating aluminum oxide shell which surround the aluminum fuel, limiting the energy release rate and application space of this materials in explosives, pyrotechnics, and propellants. Other mechanisms for nanoparticle oxidation have been proposed, such as the melt dispersion mechanism, which would overcome the diffusion limitation of aluminum energy release and expand their applications. Unfortunately, these mechanisms are difficult to observe directly, which means they are not well understood and highly debated. This thesis aims to investigate the oxidation mechanisms of aluminum micro- and nanoparticles by exploring their behavior at a particle level via high precision targeted photothermal heating. Chapter 2 reports the investigation of single aluminum nanoparticles' response to optical irradiation with various intensities and pulse widths. Results suggest that diffusion is likely driving a two- step spallation process with diffusion driven oxidation and secondary temperature elevation causing spallation. Chapter 3 reports the response of aluminum microparticles to optical irradiation. Results indicate that the observed reactions and simulated heating response are consistent with thermomechanical spallation such as melt dispersion. Chapter 4 outlines the response of isolated AL/MoO3 nanothermite composites to optical irradiation. The results indicate that the process is driven again by two stage diffusive oxidation and secondary chemical reaction induced spallation. Chapter 5 reports the employment of automation in aluminum particle experimentation to accelerate the experimental throughput. Results indicate that such automation increases throughput by 100- 2000 times over a human researcher.Includes bibliographical references
