Surface treatment-Zinc plating

Zinc plating is also called electro-galvanizing. It uses electrolysis equipment to degrease, pickle, and then put the pipe fittings into a solution composed of zinc salts, and connects the negative electrode of the electrolysis equipment. Place a zinc plate opposite the pipe fittings and connect it to the electrolytic When the positive pole of the equipment is powered on, a layer of zinc will be deposited on the pipe fittings by using the directional movement of current from the positive pole to the negative pole. Cold-plated pipe fittings are processed first and then galvanized.
1. Principle
Because zinc is not easy to change in dry air, but in humid air, a very dense zinc carbonate film can be formed on the surface, which can effectively protect the interior from corrosion. And when the coating is damaged for some reason and a small base is exposed, the zinc and the steel base form a micro-battery, so that the fastener base becomes the cathode and is protected. It is widely used in automobile transportation and other industries, but what is needed is a trivalent chromium passivation layer and a zinc-nickel alloy plating sealing coating to reduce the harmful and toxic layer of hexavalent chromium passivation.
2. Performance characteristics
The zinc coating is thicker, crystallized finely, uniformly and without pores, and has good corrosion resistance; the zinc layer obtained by electroplating is relatively pure and corrodes slowly in acid, alkali and other mist, and can effectively protect the fastener matrix. The zinc coating is treated with chromic acid After passivation, it forms white, colored, military green, etc., which are beautiful and have certain decorative properties. Since the galvanized layer has good ductility, it can be cold punched, rolled, bent and other forming without damaging the coating. .
3. Application scope
The fields involved in electro-galvanizing are becoming more and more extensive. The application of fastener products has spread throughout machinery manufacturing, making galvanized chain link fence, electronics, precision instruments, chemical industry, transportation, aerospace, etc. It is of great significance in the national economy.

Post time: Dec-01-2023