Coating of Aluminum with High Deposition Rates through Extreme High-Speed Laser Application

Abstract

AbstractIn the past few years, the Extreme High-Speed Laser Application (EHLA) process has been used as a coating technology alongside conventional processes due to its unique process characteristics and as an economical and sustainable alternative to traditional technologies. Compared to other LMD processes, the main energy input is into the powder material instead of into the substrate. This potentiates the achievement of to significantly higher surface and deposition rates as well as the coating of heat-sensitive substrates. Moreover, this increase in resource efficiency leads to a more sustainable and economically attractive process. To reduce component´s weight as well as secondary energy consumption, aluminum has become an essential base material in most industrial sectors. Aluminum is not simple to process its resistance is comparatively small due to its low hardness in relation to widely used steels. The low melting temperature of aluminum (approx. 750 °C) poses a great challenge when coating with, for example, iron-based alloys. Another challenge for laser-based systems is the reflectance of aluminum in the wavelength range of conventional laser beam sources (approx. between 1030 and 1070 nm). Therefore, for conventional laser-based processes, laser beam sources in other wavelength spectra, e.g., green or blue, are being developed to improve the processing of aluminum. Currently, commercially available multi-kW lasers in the visible light spectrum are still below the available power of IR-beam sources. In the context of this study, the feasibility of coating aluminum mase materials using EHLA is investigated. Besides the feasibility, the focus is to determine the maximum achievable surface and deposition rates up to the utilization of the available 8 kW infrared laser powder.