Rust, commonly referred to as oxidation, occurs when iron or metal alloys that contain iron, such as steel, are exposed to oxygen and water for a long period of time. While only iron or alloys that contain iron can rust, other metals can corrode in a similar way. What sets certain metals apart, is the duration of time it takes for them to begin rusting or corroding. Copper does not rust, however, it does corrode. Commonly seen on old pennies, the famous, beautiful green “patina” can actually take up to 20 years to fully form. Aluminum is one of the most commonly used metals on the planet, and it’s arguably most famous for not rusting.

Source: Tampa Steel