Laser-based production of thin wear-protection films

Abstract

Wear-protection coatings are widely applied in the automotive industry to improve tribo-mechanical properties of highly stressed engine components. Today these coatings are produced by physical vapor deposition (PVD) which is a very time consuming production-step. Wet-chemical processes based on nanoparticulate materials have a high potential to be an energy and resource efficient technique to produce functional coatings, as they are free from any need for expensive vacuum technology and any other elaborate equipment. The major challenge of the process under investigation in this paper is to adapt a laser-based thermal post treatment to turn the applied dried film into a densely-packed layer with the desired properties. Thus the in-line capable process that is introduced is a key step to obtain protection layers on various substrate-materials with low thermal stability. Short interaction times between laser beam and work piece offer the possibility to achieve the necessary high peak-temperatures in connection with short heat penetration depths.In order to select an appropriate coating material different materials provided by Merck KGaA, Darmstadt are characterized regarding their optical properties by fitting a physical model for the layer permittivity to measured transmittance and reflectance spectra in the wavelength range 250 – 2500 nm. A finite element method is used to simulate the induced temperature-time-profiles at the surface of a coated substrate. Based on the simulation laser treatment experiments are carried out to achieve densification of the films.Wear-protection coatings are widely applied in the automotive industry to improve tribo-mechanical properties of highly stressed engine components. Today these coatings are produced by physical vapor deposition (PVD) which is a very time consuming production-step. Wet-chemical processes based on nanoparticulate materials have a high potential to be an energy and resource efficient technique to produce functional coatings, as they are free from any need for expensive vacuum technology and any other elaborate equipment. The major challenge of the process under investigation in this paper is to adapt a laser-based thermal post treatment to turn the applied dried film into a densely-packed layer with the desired properties. Thus the in-line capable process that is introduced is a key step to obtain protection layers on various substrate-materials with low thermal stability. Short interaction times between laser beam and work piece offer the possibility to achieve the necessary high peak-temperatures in connec...