Numerical modeling of contact erosion including both vaporization and sputter erosion

The erosion of contact material is one of the critical failure mechanisms in switch devices. Thus it is important to study the characteristics of contact erosion. In this paper, a two-dimensional magnetic hydrodynamics (MHD) is established to get physical characteristics of the molten pool in cathode. Gas dynamics and statistical methods are then used for the calculation of the vaporization rates and sputter rates. The deformation of the geometry is calculated using the volume of fraction method (VOF). According to simulation results, the Marangoni stress plays a major role in molten pool flow which can determined the shape of the molten pool. Compared with the erosion model without consideration of evaporation below boiling point, the surface temperature and sputter rate is lower when the evaporation below boiling point is considered. The results also show that the temperature is relatively lower after considering the deformation.