Zinc is a kind of active metal. If it is not post-treated well after zinc plating, the coating will soon become dark and white corrosion products will appear successively. To reduce the chemical activity of zinc, a chromate solution is often used for passivation treatment to form a layer of chromate conversion coating on the surface of the zinc layer. The official name of this film is called "chromate conversion film" or "galvanized layer passivation film." This film-forming process is called "galvanizing passivation." The polymer emulsion can improve passivation speed, salt spray resistance, and protection of the passivation layer