First-Principles Study on the Effect of Si Atoms on the Stability and Bonding Properties of Fe/Zn Interface

The stability of the Fe/Zn interface during the hot-dip galvanizing process critically influences the coating’s quality and service performance. In this investigation, the impact of silicon atom positioning on the stability, bonding strength, and electronic structure of the Fe/Zn interface was systematically examined through first-principles calculations grounded in density functional theory, employing the CASTEP software and the GGA-PBE functional. By constructing the FeSi and ZnSi disordered solid solution models, low-energy stable configurations were selected, and 24 ZnSi/FeSi interface models (misfit < 5%) were further established. The interfacial adhesion work, interfacial energy, and electronic structure parameters were systematically calculated. The findings indicate that the position of Si atoms significantly affects interface stability, with Si atoms located on the Zn side exerting a more pronounced influence than those on the Fe side. The interfacial stability is optimal when the Si on the Fe side is far away from the interface and the Si on the Zn side is located at the interface. Notably, the S11Z32 model exhibited the highest adhesion work (4.763 J/m2) and the lowest interface energy (0.022 J/m2). This study elucidates the regulatory role of Si atoms in stabilizing the Fe/Zn interface and provides a theoretical foundation for optimizing the hot-dip galvanizing process and guiding the design of novel materials.