Effect of Ion Types on Arc Erosion of Circuit Breaker Contact: Molecular Dynamics Simulation Study

SF6 circuit breakers are commonly used as switchgear devices in high-voltage power systems. During arcing process, the particles in arc plasma are mostly positive ions (metal ions, S ions, and F ions) and electrons at temperatures beyond 15000 K. Arc erosion on the cathode surface is dominantly determined by positive ion bombardment. Thus, studying the effect of ion type and energy on arc erosion of different contacts is helpful for understanding the failure mechanisms. The current research undertakes an investigation into the impacts of Cu, S, and F ions, all with a constant energy of 50 eV, on both Cu and graphene-covered Cu substrates. Utilising molecular dynamics (MD) simulation, results reveal that S ions induce more substantial damage to the Cu substrate than Cu and F ions. Cu ions have a high sticking probability to the Cu surface, and the larger size and heavier weight of S ions mean more damage than F ions with the same incident ion energy. Moreover, graphene on the surface significantly mitigates the damage caused by all three ion types, as graphene aids in energy dissipation by oscillating waves, thereby reducing the energy acting on the underlying Cu. This research provides insights into the interaction between different plasma ions and contact materials, contributing to the improvement of contact materials.