Laser surface texturing and the performance of tribological surfaces interacting with slurries
A very challenging part of engineering is the reduction of friction forces. Over the past years, laser surface texturing (LST) has been identified as one of the most promising means to achieve this goal. This holds true for dry as well as for lubricated sliding. However, many real-world applications show a more complex picture then such laboratory model experiments. Abrasive particles are present in various tribological systems, thus motivating the study of LST and the interplay of such textures with granular media. First experiments utilizing differently laser surface textured bearing steel (100Cr6) samples were carried out with slurries as the surrounding medium. The comparison of the Stribeck curves obtained for textured and untextured surfaces obtained for slurries with different particle sizes shows that certain laser-textured surfaces can effectively reduce the friction coefficient significantly. To shed light on the acting mechanisms, the impact of such laser textures on the friction coefficient during different stages of sliding – in the boundary, mixed and hydrodynamic lubrication regime – were analyzed. 3D optical profilometry and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) were used to analyze the surface before and after the tribological test. First insights into these mechanisms will be presented.