BECOMES CORRODED can be described as the process of rusting, which is a chemical reaction that occurs when iron and oxygen come into contact with water or moisture in the air. Rusting is a common form of corrosion that causes metal to deteriorate over time. Rusting is an oxidation reaction that results in the formation of iron oxide, which is a reddish-brown substance. Rusting can cause metal to become weak and brittle, leading to structural damage.