It is a type of coating that protects metal surfaces from chemical or electrochemical corrosion caused by the atmosphere, seawater, and other factors. It is mainly divided into two categories: physical and chemical rust-preventive paints. The former relies on the appropriate combination of pigments and paint materials to form a dense film that prevents the intrusion of corrosive substances, such as iron red, aluminum powder, and graphite rust-preventive paints. The latter depends on the chemical rust-inhibiting effect of anti-corrosion pigments, such as red lead and zinc yellow rust-preventive paints. These are used for rust prevention in metals such as bridges, ships, and pipelines.