Aluminum and silver are far apart on the electrochemical series with
silver the much more noble metal. Sterling silver would be a little
lower on the scale but the silver and the copper will still be
protected against pure aluminum. aluminum does acquire an oxide film
on any air exposure.
Aluminum oxide is an electrical insulator and anodizing increases
this film thickness. this does protect aluminum from corrosion to
some extent as long as the film is undamaged. Unfortunately I have no
data that will give any on the degree of protection.
Protection would be proportional to the actual oxide film thickness,
film condition, and the electrolyte. If totally dry it may survive
considerable exposure. I can’t quantify this statement.