Industrial lubricants environmental impact

In case of aluminum, a pretreatment is necessary to achieve a long-term-corrosion-resistant adhesion. Whereas in the aerospace industry, anodizing processes are state of the art, automotive industry has been looking for more cost-effective solutions. A Cr (VI) passivation provided the best results and is now used as benchmark for new chrome-free pretreatments necessary due to the environmental impact of chrome. The best and most cost-efficient results are reached with a passivation of the aluminum in a coil coating process. But this implies that the lubricants needed for the drawing of the aluminum sheets is compatible with the adhesive. Otherwise a separate washing process of the stamped parts would be necessary which is not really economic. A new article from Rechner et al. (Rechner et al. 2010) discusses different surface pretreatments. 

---