Unraveling the adhesive properties, thermal stability, and initial diffusion mechanisms of Al/NiO nanothermites with various dominant surfaces: A first-principles study

Abstract

The interfacial region of a nanothermite plays a dominant role in its performance. One current challenge is to tune the interfacial structure and interfacial interactions to achieve the desired performance. We performed first-principles calculations and ab initio molecular dynamics simulations to disclose the significant differences in the interfacial structure, bonding strength, interfacial energy, and thermal stability of Al/NiO nanothermites with various dominant surfaces. For the Octo-Top configuration, the interdiffusion can occur at room temperature. Al diffuses into the NiO layer and O diffuses into the Al layer, resulting in the formation of a mixed interface. The kinetic stability of the other two interfacial configurations, (1 0 0)-O-Top and (1 1 1)-Top, is higher than that of Octo-Top. The presence of vacancies or defects in the interface area is detrimental to the stability of the system. Our work may provide a theoretical insight for optimizing the interfacial structure of Al/NiO at low temperatures.