New zinc-magnesium coatings for steel sheets with improved laser weldability

A new processing route is introduced for assisting robot-aided car body welding in automotive industry. Galvanized steel sheet is used as starting material. The continuous processing route is characterized by a combination of Mg alloy PVD and a subsequent thermal treatment. As a result a corrosion resistant functional graded composite coating structure is obtained in which now the Zn sub-coating is covered by the MgZn2 top-coating.