Do I need to passivate a system constructed of AL-6XN?
Yes, studies have been performed comparing AL-6XN and 316L stainless steel and the benefit of passivation. AL-6XN will form a passive surface on the steel just like 316L. As with any system, cleanliness is key. It is imperative that any oxides from welding, oils, cutting fluids, etc. be removed after installation in order for the passive surface to form to its full extent, therefore giving the best overall protection and corrosion resistance.