Textured Coating or Coated Texture: Femtosecond Laser Texturing of Dlc-Based Coatings for Dry Friction Applications

Abstract

The laser texturing is an established method for enhancing the PVD coatings tribological performance. To achieve this enhancement, two different strategies can be applied: a laser texturing of substrates before a deposition of a coating, or laser texturing of a deposited coating. Technological and economical problems of tuning laser parameters for different types of substrate can be significantly eliminated by laser texturing of already coated substrates. Nerveless, the effect of structural changes caused by laser ablation on friction performance is not well studied. In this work, we investigated the differences in these two strategies on example of commercially available DLC-based coatings.  The XPS, FIB, SEM and EDS results revealed that femtosecond laser texturing causes minor oxidation and graphitization of the DLC-based coatings but only in a few top nanometers. Macroscale tribological tests reveal no statistically significant difference in tribological performance between samples manufactured using two different strategies irrespective of pattern type and tribotest parameters. This means femtosecond laser texturing of the coated substrates can be implemented in industry like a more economically beneficial.

Keywords: DLC, laser texturing, tribology, Dry friction