Fraunhofer Institute for Laser Technology ILT is developing laser-based manufacturing processes to apply PFAS-free functional coatings to industrial components, including large plain bearings, seals and other parts relevant for the wind energy sector. PFAS (per- and polyfluoroalkyl substances) have traditionally been used in applications requiring low friction, wear resistance and protection against harsh operating conditions. However, regulatory pressure on these substances is increasing due to their persistence in the environment. Replacing PFAS-based coatings requires not only alternative materials but also suitable processes to apply them reliably to components exposed to high mechanical loads.
Within the RePEEK and EPOS projects, Fraunhofer ILT is investigating laser-based methods to apply polyetheretherketone (PEEK) coatings as an alternative to PTFE-based systems. One potential application is large plain bearings used in wind turbines, where coatings help reduce friction between rotating shafts and bearing surfaces.
Conventional PEEK coating methods often require components to be heated in large furnaces, which can be energy-intensive and challenging for heavy components. The laser-based process developed by Fraunhofer ILT applies and melts the coating material locally, reducing thermal stress on the component while enabling controlled coating of large surfaces.
In the RePEEK project, researchers are developing a process in which a laser first creates a metallic surface layer to improve adhesion before PEEK powder is applied and melted into the structure. The resulting coating combines a metallic functional layer with a PEEK-based top layer.
The related EPOS project focuses on applying PEEK coatings in multiple layers to large plain-bearing components. The approach aims to achieve thicker coatings without requiring the complete component to undergo high-temperature furnace treatment.
Other Fraunhofer ILT projects are addressing PFAS-free coatings for elastomer rollers and sealing systems. The pureWaterSeal project, for example, combines PFAS-free sealing materials with water-based lubricants. Researchers are using laser structuring of diamond-like carbon (DLC) coatings to reduce friction and improve wear resistance.
