Current research in production technology focuses primarily on increasing resource efficiency. In the mobility sector in particular, reducing energy requirement is of crucial importance. To increase resource efficiency, high-strength aluminum alloys play an important role due to their outstanding specific strength. However, the high-strength aluminum alloys of the 7000 series can only be hot formed. Thereby, their high adhesion tendency at typical hot forming temperatures exceeding 450 °C require the development of customized anti adhesive coatings for the forming tools.
Therefore, the subproject A4 of the LOEWE project ALLEGRO (high-performance components made of aluminum alloys through resource-optimized process technologies) set itself the goal of identifying PVD or PA-CVD coatings that significantly reduce or even completely prevent the tendency of the aluminum alloy to adhere to the tool.
For this purpose, TiN, TiAlN, Cr, CrAlN, ZrN, ZrO and ZrON PVD coatings as well as DLC and Si-DLC PA-CVD coatings were produced and characterized with respect to chemical, structural and mechanical properties. The adhesion tendency was examined in a pin-on-disc tribometer test at temperatures up to 350 °C. Furthermore, the influence of a surface structuring on the adhesion tendency was analyzed.