At room temperature, the main corrosion forms are chemical corrosion and electrochemical corrosion. Chemical corrosion is caused by the direct chemical interaction between the metal substrate surface and the non electrolyte. The reaction is characterized
by the direct oxidation-reduction reaction between the atoms on the substrate surface and the oxidants in the non electrolyte to form corrosion products. Electrochemical corrosion is caused by the electrochemical reaction between the metal substrate
surface and the ionic conducting electrolyte. Any corrosion reaction carried out by electrochemical mechanism includes at least one anode and one cathode reaction, and the circuit is formed by the electron flow inside the metal substrate and the ions
in the electrolyte. Electrochemical corrosion is common and common corrosion. The corrosion of metals in the atmosphere, seawater, soil and various electrolyte solutions belongs to this category.
There are many ways to control and protect the metal corrosion, among which the way to prevent the steel from the external medium by coating is common in the sheet metal. These coatings are mainly divided into metal coating and non-metal coating.
Baosteel Qingshan gray color coated roll - quality
There are two kinds of galvanizing products for building color coated baseplate: plating and alloy coating. Their performance differences and applications are as follows:
Hot dip galvanizing
The hot-dip galvanizing here refers to the hot-dip pure zinc, which is widely used in construction. It has been widely used in the construction industry before it was used as the color coated base plate. At present, it is the main type of color coated
base plate for construction. Good corrosion resistance. It is suitable for making building exterior board. It can be used for general forming, stamping, deep stamping and other levels of processing.
Hot dip aluminizing
The coating composition of the product is about 55% aluminum, 1.5% silicon, the rest is zinc (43.5%). It is characterized by excellent atmospheric corrosion resistance, 2-6 times of that of galvanized sheet, and excellent corrosion resistance.
It also has high temperature corrosion resistance, smooth surface and good appearance, but the forming and weldability of the coating is slightly poor. It is suitable for making building exterior board, and can be processed in general molding, mechanical
bite and other levels.
Hot dip galvanized aluminum
The coating consists of 5% aluminum, 0.1% mixed rare earth elements and the rest of zinc. Its characteristic is that the coating has good formability, and its atmospheric corrosion resistance
is 2-3 times of that of hot-dip galvanized sheet. Good coating and welding performance. Compared with hot-dip aluminized zinc steel plate, zinc flower is small and seldom used.