All aluminum is corroded. All of it.Oxidation on aluminum is aluminum-colored. The oxidation film on aluminum seals out oxygen, so no more oxidation will take place. This can't continuously happen with aluminum because the oxygen can't get through the layer.
This green substance is called copper carbonate. The process that causes copper carbonate to form is called oxidation.The greenish tint on the copper is often referred to as patina.When copper is first oxidized, it does not immediately turn green. Oxidation is a process. The copper may turn black or dark brown. Gradually, shades of green may appear. Many times, the layer of copper patina is thin. The patina is considered by some to be waterproof and a desired effect.
