What is the principle of cold galvanizing

(1) Cold galvanizing
Cold galvanizing, also known as electroplating, is the process of using electrolytic equipment to remove oil, acid wash, and then place the pipe fittings in a solution containing zinc salts. The negative electrode of the electrolytic equipment is connected, and a zinc plate is placed opposite the pipe fittings. The positive electrode of the electrolytic equipment is connected to the power supply, and a layer of zinc is deposited on the pipe fittings by using the directional movement of the current from the positive electrode to the negative electrode. Cold galvanized pipe fittings are processed first and then galvanized.
① Principle
Due to its resistance to change in dry air, zinc can form a dense zinc carbonate film on the surface in humid air, which can effectively protect the interior from corrosion. And when for some reason the coating is damaged and a relatively small substrate is exposed, zinc forms a micro battery with the steel substrate, making the fastener substrate a cathode and protected. It is widely used in industries such as automobile transportation, but what is needed is a trivalent chromium passivation layer and a zinc nickel alloy coating to reduce the harmful and toxic layer of hexavalent chromium passivation.
② Performance characteristics
The zinc coating is thick, with fine and uniform crystallization without pores, and good corrosion resistance; The zinc layer obtained from electroplating is relatively pure and corrodes slowly in acid, alkali and other mist, which can effectively protect the substrate of fasteners. The galvanized layer forms white, colored, military green, etc. after chromate passivation, which is beautiful and elegant, and has a certain degree of decoration. Due to the good ductility of the galvanized layer, it can be formed through various processes such as cold stamping, rolling, bending, etc. without damaging the coating.
③ Application scope
The fields involved in electrogalvanizing are becoming increasingly extensive, and the application of fastener products has spread to mechanical manufacturing, the production of galvanized wire mesh, electronics, precision instruments, chemical engineering, transportation, aerospace, and other areas, which are of great significance in the national economy.