Study on the Size Dependence of the Shell-Breaking Response of Micro/Nano Al Particles at High Temperature

The reactivity of Al nanoparticles is significantly higher than that of micron Al particles, and the thermal reaction properties exhibit notable distinctions. Following the previous studies on micron Al particles, the shell-breaking response of Al nanoparticles under vacuum conditions was analyzed using COMSOL simulation. Relationships between thermal stabilization time, shell-breaking cause, shell-breaking response time, and particle size were obtained, and a systematic analysis of the differences between micrometer and nanometer-sized particles was conducted. The results indicate that the thermal stabilization time of both micrometer and nanometer particles increases with the enlargement of particle size. The stress generated by heating Al nanoparticles with sizes ranging from 25–100 nm is insufficient to rupture the outer shell. For particles within the size range of 200 nm to 70 μm, the primary cause of shell-breaking is compressive stress overload, while particles in the range of 80–100 μm experience shell rupture primarily due to tensile stress overload. These results provide an important basis for understanding the shell-breaking mechanism of microns and nanoparticles of Al and studying the oxidation mechanism.