Study on the effect of particle size on early oxidation characteristics of aluminum nanoparticles

Abstract

Aluminum nanoparticles (ANPs), as a high-energy material, were widely used in military and civilian fields. In this study, molecular dynamics simulation with the reactive force field (ReaxFF) was used to study the oxidation process of five different particle sizes (3 nm, 4 nm, 5 nm, 6 nm and 7 nm) of ANPs. The formation mechanism of surface chain-like alumina during the ANPs oxidation process. The relationship between oxide layer thickness and active aluminum content with time was obtained. The results indicated that there were two stages in the oxidation process, i.e. the rapid oxidation stage (0–3 ps) and the slow oxidation stage (3–10 ps). Between 0 and 10 ps, the average growth rates of ANPs oxide layer were 0.250 nm/ps, 0.071 nm/ps, 0.053 nm/ps, 0.037 nm/ps, 0.038 nm/ps, respectively; and the average reduction values of active aluminum content per ps were 16.7%, 7.3%, 5.1%, 3.1%, 2.9%, respectively.