The thickness of the electroplated zinc layer is usually 5 to 15 m, and the hot dip galvanized layer is generally 35 m or more, or even as high as 200 m. Hot galvanized coating ability, dense coating, no organic inclusion. It is well known that the mechanism of zinc corrosion against atmospheric corrosion has mechanical protection and electrochemical protection, in the atmospheric corrosion conditions, the surface of zinc layer of ZnO, Zn (OH) 2 and basic zinc carbonate protective film, to some extent slow down the corrosion of zinc, which Layer protection film (also known as white rust) will be destroyed and the formation of a new film. When the zinc layer serious damage to the iron matrix, the zinc on the substrate electrochemical protection, the standard potential of zinc -0.76V, the standard potential of iron -0.44V, zinc and iron to form a micro-cell as the anode is dissolved zinc, iron As the cathode is protected. It is clear that hot-dip galvanizing is superior to electro-galvanizing in resisting atmospheric corrosion of the base metal iron.
