Dual-beam laser-based processing of tribological polymer coatings

Abstract

Polyether ether ketone (PEEK) is a potential candidate to substitute state-of-the-art friction-reducing coatings due to its excellent properties in terms of temperature resistance and friction reduction. Conventionally, microparticulate PEEK is applied to a component and melted in an oven-based process where the entire component is heated above the melting temperature of PEEK (Tmelt = 340°C) for minutes to hours. Due to the high thermal load on the component, temperature-sensitive materials cannot be processed without a significant reduction in the hardness of the component. One approach to overcome this drawback is to melt the microparticulate PEEK layer with laser radiation. Due to the achievable high heating and cooling rates, laser treatment offers the possibility to obtain the necessary melting temperature within the coating while reducing the thermal load on the substrate material. Still, a pre-heating of the substrate surface is necessary to achieve a high PEEK layer adhesion to the substrate surface. In this study, a laser-based dual-beam approach is presented in which both the preheating of the substrate and the melting of the PEEK layer are implemented with laser radiation.