The principle of zinc protection is that the mechanism of zinc’s anti-corrosion has two protections. 1.Mechanical protection 2. Electrochemical protection.
When subjected to corrosion, there are basic zinc carbonate protective film and ZnO and Zn(OH)2 on the surface of the zinc layer; it can reduce the degree of corrosion. This protective film (ie “white rust”) will form a new film if it is damaged. If the galvanized layer is severely damaged and will corrode to the iron matrix of the workpiece. The zinc will protect the iron matrix of the workpiece.
The standard potential of zinc is -0.76V, and the standard potential of iron is -0.44V. When zinc and iron form a micro-battery, zinc will become the anode and be dissolved, and iron will become the cathode and be protected.
Electro-galvanizing uses chemical principles to separate the zinc alloy into zinc ions, which are attached to the surface of the workpiece.
Generally, the electro-galvanized zinc layer is very thin, and the electro-galvanized workpiece is prone to rust in the general environment. Generally, electro-galvanizing is used for the anti-corrosion of various steel products and structures. The zinc of the electro-galvanizing layer is very small, only 10-50g per square meter.
Essentially different.
Hot-dip galvanizing, also known as hot-dip galvanizing, is a galvanizing method in which steel components are immersed in molten zinc to obtain a zinc coating.
After degreasing, pickling, dipping, and drying, the steel components are immersed in the molten zinc solution for a certain period of time, and then they can be taken out.
Galvanizing, also known as cold galvanizing. It is to use electrolysis equipment to degreasing and pickling the workpiece to be processed, then put it into a solution of zinc salt, and then connect the negative electrode of the electrolysis equipment.
1.Place a zinc plate on the opposite side of the processed workpiece.
2. Connect it to the positive electrode of the electrolysis equipment.
3. Turn on the power, and use the current to move from the positive electrode to the negative electrode, and a layer of zinc will be deposited on the surface of the processed workpiece.
The difference between electro galvanized and cold galvanized:
1. Different corrosion resistance, hot-dip galvanizing is dozens of times that of cold galvanizing;
2. The method of operation is different: hot-dip galvanizing is galvanized in a molten zinc solution of 450-480 degrees.
And cold-dip galvanizing is galvanized by electroplating or other methods at room temperature;
3. The thickness of the galvanized layer is different. The thickness of hot-dip galvanizing is much greater than that of cold-dip galvanizing;
4. The surface smoothness is different. The appearance of cold galvanizing is smoother and better than that of hot galvanizing;
5. The price is different, the price of hot-dip galvanizing is higher than that of cold-dip galvanizing.
6. Cold galvanizing can only be plated on one side, and hot-dip galvanizing must be fully plated;
7. Different adhesion, cold galvanizing is not as good as hot galvanizing;
8. The charging standards are different. Hot-dip galvanizing is charged according to the thickness of the material. Cold-dip galvanizing is mostly charged according to square meters.
9. The service life is different: the hot-dip zinc-compliant zinc layer can generally be used for more than 20 years;
The electro-galvanized zinc layer can generally be used for 2 to 5 years.
Post time: Dec-27-2021