Investigation of the laser-assisted wire arc spraying process

• Applicants: Professorin Dr.-Ing. Kirsten Bobzin; Dr.-Ing. Jörg Hermsdorf
• Subject Area: Coating and Surface Technology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 548719456

In comparison to other thermal spraying processes, Wire Arc Spraying (WAS) is characterized primarily by higher deposition rates. However, coatings produced by WAS have so far only been achieved with comparably low bond strength. As part of the substrate preparation before the coating process, the substrate surface is usually roughened by conventional sandblasting. Consequently, the blasting material often remains on the substrate surface, adversely affecting the bond strength between the substrate and the coating material. To improve the adhesive bond strength, laser beam sources are already being used in addition to Thermal Spraying. However, to date, static laser beams have only served as a heat source for preheating and roughening the substrate. In this research project, the laser beam is moved together with the WAS as a single unit. Initial experiments show that the application of coatings with laser-assisted WAS is possible without substrate preparation. The goal of the proposed project is to develop a fundamental understanding of the laser-assisted WAS process, to quantify its influencing factors, and to investigate the relationship between process parameters and resulting layer properties. Alongside the experimental development of the process, a numerical model is to be developed for the fundamental investigation of the thermally induced profile, which is necessary for the realization of a material-to-material bond. The interaction between the spray additive materials and the thermally induced profile by oscillating laser radiation during laser-assisted WAS will be examined. The model developed within the scope of the project is based on an existing droplet impact model and extends it with the input parameters of the laser beam. The model aims to describe the physical fundamentals of the process outcome and serve as an efficient tool for process development. Based on the model, process parameters for the laser-assisted WAS are to be predicted in this research project and evaluated through experimental investigations. From the determined process window, the influence of the process variables on the coating properties and the correlation of the process variables will be quantified using design of experiments.

• DFG Programme: Research Grants