- Sep 11, 2018 -
Previously, various types of zinc-nickel alloy plating solution systems have been studied. The electroplating solutions used in industrial production to date are mainly alkaline and acid chloride types. The nickel content in the electroplated layer obtained by the former is generally 5% to 10% by weight, and the latter can obtain a plating layer having a nickel content of more than 10%. The biggest advantage of alkaline electroplated zinc-nickel alloy is that the uniform plating ability is good, the coating thickness is relatively uniform, and the corrosiveness of the plating solution is weak. Its disadvantages are low current efficiency, slow deposition rate of the coating, and corrosion resistance and brightness of the coating are not as good as those of the zinc-nickel alloy coating obtained from the acidic fluoride type. In addition, another disadvantage of alkaline zinc-nickel alloy plating is that it cannot be used for surface plating of high carbon steel and cast iron parts. On the contrary, the advantages of acid fluoride electroplated zinc-nickel alloy are: high current efficiency, fast deposition speed, corrosion resistance and brightness of the coating are generally high, and also suitable for high carbon steel, The surface of the cast iron is plated.
Similar to electroplating, in order to improve the corrosion resistance of the zinc-nickel alloy coating, increase its decorative properties, and improve the bonding between the coating and the base metal, the electroplated zinc-nickel alloy is also subjected to chromate passivation after the end of electroplating. A transparent film with a dense structure and a dense structure is formed on the surface. Zinc-nickel alloy passivation film is colorless, color (also known as yellow), black, earthy gray.