Innovative Laser Sources in the Micro- and Nanostructuring of Coated Functional Surfaces (Keynote)

Research works and industrial applications demonstrated that laser structured surfaces can exhibit enhanced tribological behaviors and increased lifetimes, as compared with similar unstructured surfaces. Laser structuring techniques based on IR beams and micro- or nanosecond pulses are nowadays already available, but they show certain limitations in the processing of coated surfaces and in microtribology. Physical features yielding these technological limits are discussed in the beginning. Through alternative laser techniques (e.g., femtosecond pulses, UV laser beams), the aforementioned drawbacks can be overcome. An overview of these novel laser systems and of their first applications in micro- and nanostructuring of surfaces is subsequently given. Two laser structuring approaches are discussed in the experimental part of this contribution: direct and indirect processing. Laser structured surfaces were tribologically tested and results of these tests are here exposed.