Does Aluminum Rust?

Aluminum corrodes but it does not rust. Rust refers only to iron and steel corrosion.

Aluminum is actually very prone to corrosion. However, aluminum corrosion is aluminum oxide, a very hard material that actually protects the aluminum from further corrosion. Aluminum oxide corrosion also looks a lot more like aluminum (dull gray to powdery white in color), so it isn't as easy to notice as rusted iron.

When iron corrodes the color changes and it actually expands. This expanding and color change can produce large red flakes that we all know as rust. Unlike aluminum oxide, the expanding and flaking off of rust exposes new metal to further rusting. This is why it is so important to provide a barrier so rust doesn't start.

While aluminium doesn't rust, it often becomes dull from corrosion, and is often encrusted with brake dust, calcium, lime, tarnish, grease, oil and hard water stains. Simply washing it off will not work, you need something stronger and more effective to do the job. We recommend Flitz Aluminum Pre-Clean to remove the surface grime, corrosion and buildup followed by Flitz polish (paste or liquid) to restore a brilliant shine. Works great on fuel tanks, gas pumps, mag/alcoa 

above information provide by Shenzhen Pengfeng metal stamping parts  fabrication