What Are The Characteristics Of Hot Dip Galvanized Coating

The presence of a compound layer is a common feature of the hot dip plating process. Unlike the bonding force between the electroplated coating and the steel base, which is an attraction between atoms, the hot-dip plated metal is not in direct contact with the steel base, but is held together by a compound formed. The characteristics of the compound are high hardness and poor plasticity, so the existence of this layer of compound greatly affects the processing performance of hot-dip galvanized products during bending and deformation and the later corrosion resistance.

Among the three coatings of hot-dip galvanizing, aluminum-plating, and aluminum-zinc alloy, the compound layer of hot-dip galvanizing is very thin, and its thickness is easy to control; it can be thinner after adding a small amount of aluminum, so At this time, the processing performance is better.

When the coating is intact, the corrosion resistance of the galvanized layer is not the best, because the corrosion product is very loose and cannot form a dense oxide film protective layer to protect the internal organization, but it can basically meet various purposes. Especially after passivation treatment, the anti-corrosion performance of the galvanized layer has been greatly improved.

After the coating is scratched and the steel base is exposed, the sacrificial anti-corrosion effect of the zinc coating shows its superiority. After the coating is scratched, the physical protection effect of the coating on the steel base disappears, and it depends on the electrochemical protection effect. Although the oxides of zinc are not very dense, this sacrificial anti-corrosion effect is strong and can protect the steel base until all the galvanized layer is corroded.