Color coated steel plate is also called organic coated steel plate or pre-coated steel plate. As a continuous production method for coils, color steel plates can be divided into two methods: electro-galvanized and hot-dip galvanized.
At the same time, electro-galvanizing is a method of making gold-plated paint-”layer zinc metal or zinc alloy” through electroplating.
Hot-dip galvanizing, also known as hot-dip galvanizing, is to dip the metal products that need maintenance into the molten zinc metal to make the appearance of the maintenance metal coating. Compared with electroplating, the metal hot-dip coating is thicker; under the same environment, it has a longer life.
The corrosion of the hot-dip galvanized layer on the steel surface is equivalent to that of pure zinc. The corrosion of zinc in the atmosphere is similar to the corrosion process of steel under atmospheric conditions. Chemical oxidation corrosion occurs, electrochemical corrosion occurs on the zinc surface, and water film condensation occurs. In a neutral or weakly acidic atmosphere, the corrosion products formed by the galvanized steel layer are insoluble compounds (zinc hydroxide, zinc oxide, and zinc carbonate). These products will be separated by deposition and form a fine thin layer.
Generally it can reach a thickness of 8μm”. This kind of film has a certain thickness, but it is not simply soluble in water, and has strong adhesion. Therefore, it can play a barrier between the atmosphere and the galvanized sheet. Prevent further corrosion. The galvanized layer is damaged during maintenance, and part of the steel surface is exposed to the atmosphere.
At this time, zinc and iron form a miniature battery. The potential of zinc is significantly lower than that of iron. As the anode, zinc has a special anode maintenance effect on the steel plate substrate to avoid corrosion of the steel plate.
Color-coated board is a kind of liquid coating, which is applied to clean metal surface by brush or roller. After heating and curing, a paint film with the same thickness can be obtained.
Post time: Nov-02-2021