*Article* **Tribological Properties of High-Speed Uniform Femtosecond Laser Patterning on Stainless Steel**

**Iaroslav Gnilitskyi 1,2,3,\*, Alberto Rota 4,5,6, Enrico Gualtieri 4,5, Sergio Valeri 4,5,6 and Leonardo Orazi 1,5**


Received: 18 July 2019; Accepted: 17 September 2019; Published: 24 September 2019

**Abstract:** In this work, an analysis of the tribological performance of laser-induced periodic surface structures (LIPSS) treated X5CrNi1810 stainless steel was conducted. The approach followed by authors was to generate LIPSS-patterned circular tracks, composed of radial straight grooves with uniform angular periodicity. This permitted to measure the tribological properties in a pin-on-flat configuration, keeping fixed the orientation between the grooves and the sliding direction. A Stribeck curve was measured, as well as the consequent wear. A deep analysis of the sub-surface conditions after LIPSS generation was moreover performed using Focused Ion Beam (FIB) cross-section.

**Keywords:** LIPSS; laser surface texturing; tribological properties; wear; Stribeck curve
