In chamber top coat

At present we base coat outside the Vacuum chamber, vacuum metallise with Al in the chamber and top coat outside the chamber. What is the best system to do all 3 in the chamber? If this is not generally done, what is the best way to at least top coat in the chamber after the metallising?

The polymer coatings you are depositing on the base and top are not generally deposited in vacuum, so, without knowing more about your application, I would say no, you can't put the same base and top coats on within the aluminum deposition chamber. It might be possible to replace all three with a suitable PVD coating, such as chromium nitride, which would be done entirely within the vacuum chamber. It really depends on the performance you need. Chromium nitride, for instance, will give you a good appearance and very high wear and scratch resistance, but it is not a "fill" coating, that is, the coating surface finish is the nearly the same as the substrate, so you may not get the sheen that you want.