Rust is a coating that occurs on the surface of iron as it oxidizes. Rust is also known as iron oxide and corrosion. This chemical compound comes in many different combinations of iron and oxygen. Rust is reddish-orange in color.
Rusting is an oxidation reaction. The iron reacts with water and oxygen to form hydrated iron(III) oxide, which we see as rust. Unlike rust, which can flake off the surface of iron and steel objects, the layer of aluminium oxide does not flake off