Femtosecond Laser-Texturing of a Novel Micro-Texture with Solid Lubricant Additives for Friction Reduction
摘要
Femtosecond laser micro-texturing of surfaces has been established as an important technology to reduce frictional losses in lubricated sliding systems. This work differs from previous studies by investigating an optimized micro-texture designed for enhanced hydrodynamic pressure generation combined with graphene and MoS2 additives to analyze their synergetic friction-reduction mechanism. First, computational fluid dynamics simulations were used to analyze the hydrodynamic pressure build-up and lubricant flow behavior of the micro-texture and film. The simulated lubricant flow pathways also provided insight into the transport of the solid lubricant particles throughout the micro-texture and lubricant film, representing another distinctive aspect of this study. A femtosecond laser was then used to precisely engrave the micro-textures, with optimized process parameters to achieve sharply defined edges, while avoiding thermal damage. Finally, the tribological behavior of the micro-texture was experimentally evaluated using a novel tribometer under different contact pressures, sliding speeds, and solid lubricant additives. When combined with solid lubricant additives, a synergetic friction-reduction effect was observed, attributed to the combined effects of the increase in the film thickness due to hydrodynamic pressure generation, solid lubricant particle retention within the texture and transport throughout the film, forming low-shear tribo-films of solid lubricant additives at the contact interface.
Graphical abstract