Metal coat is a term used to describe a protective layer of metal that is applied to a surface. RUST is a type of corrosion that occurs when iron or steel is exposed to oxygen and moisture, and it is typically prevented by applying a metal coat. PLATE is a thin sheet of metal that is applied to a surface to provide protection from RUST and other forms of corrosion. PATINA is a thin layer of oxidation that forms on the surface of metal over time, and it can also be used as a protective coating.