On your second question, aluminium does rust, but the 'rust-dust' is more dense than for example that of iron and because of this higher density it isolates the underlying non-oxidated aluminium. So in fact, when pure aluminium is put in air, it immediately creates (rusts) its own protective layer. Or at least that's what I remember of that chemistry class.
Gold doesn't rust though, so perhaps that'll work in whatever you're plotting to use it on
