Chain often has a finish to increase the durability and overall performance of the chain or to provide an aesthetic appearance. A particular finish may be desired depending on the application of the chain, whether it may be used for decorative purposes or needs to withstand corrosion. This article discusses the benefits each finish may provide. Let’s take a look at the types of finishes our chain may come in:
The term “self-colored” simply means the chain does not have a finish or coating on it.
A consistently dark finish, black zinc chain is typically zinc plated, and then black or grey passivated to give it the color. It is typically a matte finish with little to no glare or reflection and is quite durable.
Chain that has a bright galvanized finish has a thin coating of zinc that has been mixed with aluminum to give it a bright or shiny finish. Bright galvanized is a standard finish on weldless chain at PCP. Tests have shown that chain made from galvanized wire is superior in rust resistance compared to chain which is zinc plated after forming. Galvanized wire has higher rust resistance because of a heavier zinc coating than zinc-plated chain.
Clear Zinc or Zinc Plated
Clear zinc and zinc plated are typically the same things. Clear zinc is a colorless finish applied over a zinc-plated item. It provides corrosion protection and gives the item a silver look that can sometimes have a blue tint. Zinc plated chain has a very thin coating of zinc deposited on the chain. Because it is mainly a cosmetic coating, it does not offer much protection against corrosion and should only be used in mildly corrosive environments.
Chain is dipped in a copper solution to give it a desired reddish appearance. In addition to a decorative finish, it also provides some corrosion protection.
Copper Dipped Chain
The hot-dip galvanized finish provides a metallurgically bonded zinc coating to protect the underlying steel from corrosion. It is useful in very corrosive applications, including marine applications.
Hot-Dip Galvanized Mooring Chain
Nickel plating gives chain an added protective layer against corrosion and increases durability. It can also make the chain brighter and more lustrous.
Chain that has a passivated finish has gone through a chemical process to improve corrosion resistance. The process removes free irons from the surface of stainless steel by dipping it in nitric or citric acid and provides a thin oxide layer to protect the underlying metal from corrosion.
Yellow chromate provides excellent corrosion protection. It refers to the color of the chromate applied to the chain after it has been zinc plated. Department of Transportation inspectors are easily able to identify chain that has a yellow chromate finish.
The majority of our plating is done in-house, including clear zinc, yellow chromate, black chromate, copper dip, and stainless steel passivation. We utilize both a continuous plating line and a barrel line for the application of zinc plating and chromate.