Noble metals such as gold and platinum do not corrode easily.
What is corrosion?
Corrosion is a natural phenomenon. Corrosion is a chemical reaction that takes place between metal and oxygen in the presence of moisture. The most active metals which tend to lose electrons easily such as magnesium and aluminium corrode easily. The most stable metals those which do not lose electrons easily such as gold and silver do not corrode easily.
Iron and corrosion
Iron is an extremely strong metal but not corrode very easily, resulting in the formation of rust. Rust causes metals to become brittle. To create rust resistance iron is often coated or mixed with metals that do not corrode easily such as nickel. Some metals do not form protective coatings. when iron coatings corrodes a flaky layer of rust forms. Rust can always lift away, allowing the metal beneath to corrode.