Surface Treatments for Large Automotive Magnesium Components

Summary

Die-Cast magnesium alloys have seen an increase in use for automotive components because of their high strength-to-weight ratio, dimensional accuracy, high integration and part consolidation with weight reduction and potential cost competitiveness. In this trend most of the bigger Automotive Industries are going to develop also Mg die-cast parts for body application like door frames, trunk frames, front ends. From here there is the strong request to develop and put into production a surface treatment that could guarantee the resistance of the part in the aggressive atmosphere environment. Among the surface treatment today available or under development anodising and fluorozirconate seem to be good compromises between corrosion and paint adhesion. In order to better evaluate these processes on industrial scale and for large components, TEKSID R&D Tech Center has recently set up a pilot plant for Mg Anodising with ANOMAG process and has tested for comparison the fluorozirconate process. Both processes have been used to treat large castings (seat frames, doors, front ends) on preproduction series.