Coating Layer Characterization of Laser Deposited AlSi Coating over Laser Weld Bead

Corrosion protection of steel components is an important topic in automotive industry. Laser beam welding makes a narrow weld bead, thus minimizing the damage to the original coating on the steel material. However, the weld bead loses its original coating and is vulnerable to corrosive attack. It was demonstrated in this study that laser beam generated AlSi coating is an effective way to apply a protective coating on the weld bead. Coatings with different thickness and topography have been deposited under different laser power and processing speed. The microstructure of the as-deposited coating and its evolution after heat treatment has been studied. EDS was employed to analyze the distribution of chemical compositions of the laser generated coatings. Several metallic compounds of Al and iron have been identified. It was found that the type of metallic compounds can be influenced by the laser processing parameters.