We are mixing multiple topics here...

First, the OP asked about preventing mechanical seizure between two
aluminum tubes... For this I prefer a molybdenum antiseize from the
auto store, or similar... I had a System One beam in the air in
Michigan for 25 years... The joints were lubed with the moly and then
the assembled joint was taped with 3M - #33 tape and the ends of the
tubes were plugged... When I sold the house and the beam came down the
tape was still on, though starting to crumble, and the tubing only need
a firm twist to slide the joints apart... The mating surfaces were
clean and still had a shine.. There was an invisible film of the moly
antiseize staining my hands and clothing after a quarter century...

Second, is the issue of blocking electrolysis between disimilar metals,
eg. copper and aluminum... For this I would use the appropriate paste,
NoAlOx is one brand... For copper to copper there is a different paste
used..

Third is the issue of slow oxidation of aluminum which causes a high
resistance joint - and possible mechanical seizure... In areas more
prone to oxidation then I might prefer NoAlOx, or similar over the moly
based antiseize for bolts... In Arizona aoxidation is a non issue... In
Tampa oxidation is the only issue...

The last topic is increasing electrical resistance of the joint when
the surface oxidizes... What the antioxidation paste has is zinc
particles in suspension that when clamped between the two metal
surfaces actually pierces the film of oxidation mechanically and
creates a lower resistance path for current flow...

denny / k8do