As a continuous coil production process, galvanized sheet can be divided into galvanizing and hot-dip galvanizing methods, in which galvanizing method is to make the Jinjingzhong painting coated with "zinc metal or zinc alloy" by electrodeposition. Hot
dip galvanizing, also known as hot dip galvanizing, is to impregnate the maintained metal products in molten zinc metal to form a maintenance metal coating on its surface. Compared with the electroplating method, the hot metal coating is thicker,
and its life is longer in the same environment.
The corrosion of hot-dip galvanized steel is equivalent to that of pure zinc. The corrosion process of zinc in atmosphere is similar to that of steel in atmospheric condition. Chemical oxidation corrosion occurs, and electrochemical corrosion occurs on
the surface of zinc condensed with water film. In neutral or weak acidic atmosphere, galvanized steel sheet is formed after corrosion. Corrosion products are insoluble compounds (zinc hydroxide, zinc oxide and zinc carbonate), which will be separated
by deposition and form a fine thin layer.
Generally, the thickness can reach 8 microns. This kind of film has a certain thickness, is not simply soluble in water, and has strong adhesion. Therefore, it can play a barrier effect between atmosphere and galvanized sheet, and avoid further development
of corrosion. The galvanized coating was damaged during maintenance. The steel part is exposed to atmospheric environment.
At present, zinc and iron constitute micro-batteries. The potential of zinc is significantly lower than that of iron. As an anode, zinc plays a dedicated role in the maintenance of the steel plate substrate and avoids the corrosion attack of the steel
plate. Colour-coated galvanized sheets are liquid coatings, which are coated on clean metal surfaces by brushing or roller coating. After heating and curing, coatings with the same thickness of stone can be obtained.
In addition to separating metals from corrosive media, the effect of paint film can also passivate metals with the help of some pigments (such as lead, zinc chromate, etc.) in the painting process to achieve permanent anti-corrosion effect. According
to the anticorrosion mechanism of colorful coated steel plate, organic coating (including solid coating and bottom coating) is a barrier material, which separates the substrate from the corrosive medium to achieve the anticorrosion effect.