Hi, I passivate aluminium parts (interlox 338 or iridite NCP) this both protects the surface and allows the part to be conductive. For me this earth bonding is very important (electroincs industry). The passivation coat also provides an enhanced base for painting too.
Hi, whilst not an extra coating electropolishing would increase its resistance to corrosion. I have used this in the marine industry to great effect. It has a chrome like apperance too.
On the downside it won't help at all with the abrasion.
I agree with you, my first pass would have been...