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Protective Properties Of Hot Dip Galvanized Coatings

- May 29, 2018 -

Generally, the thickness of electrogalvanizing layer is 5 ~ 15 centile m, while the hot-galvanizing layer is generally more than 35 centile m, or as high as 200 centile m.The coating capability of hot galvanizing is good, the coating is compact, no organic matter inclusion.As is known to all, the mechanism of resistance to atmospheric corrosion of zinc have mechanical and electrochemical protection, under the condition of atmospheric corrosion of zinc layer surface of ZnO, zinc (OH) 2 and alkali carbonate zinc coating, to a certain extent reduce the corrosion of zinc, this layer of protective film (also called white rust) is damaged and will form a new film.Destroyed when the zinc layer, endanger the iron matrix, the zinc electrochemical protection on the substrate, the standard potential of zinc - 0.76 V, iron the standard potential of 0.44 V, zinc and iron to form the micro battery zinc as the anode is dissolved, iron are protected as the cathode.It is obvious that the resistance of hot galvanizing to atmospheric corrosion of matrix metal iron is better than that of electric galvanizing.