Many OEMs are aware of the benefits offered by zinc plating. They may not be aware of the different processes, and when each process is the best choice. Understanding the basics of zinc acid and zinc alkaline plating helps the OEM in talking to a metal finishing company and evaluating the type of services they provide and the quality of the plating for parts they can produce.
The Use of Zinc Plating
In general, plating of all types is used to create a protective surface on metals and alloys that naturally rust. This is not just for aesthetic reasons, as surface oxidation of metal parts can result in shortening the life cycle of the part as well as increasing the risk of part failure over time. Rust on the surface of parts that move in a system is particularly problematic. It can prevent movement, increase wear, and decrease efficiency. In addition, rust flakes in systems, especially in the automotive industry, can result in serious damage to other engine components.
The choice of either zinc acid or zinc alkaline plating can prevent these types of issues by providing a thin coating of zinc over the surface of the metal. This is true even when parts are exposed to chemicals or water.
Acid Zinc
The choice of a zinc acid plating process produces a very high level of shine and brilliance on the surface of the part. It is typically used with hardened steel, but it can also be used on cast iron. In many cases, the zinc acid plating process is not followed by another coating.
Alkaline Zinc
The choice of zinc alkaline plating is a non-cyanide plating option that provides a pearlescent finish on the metal. It is cost-effective and used widely throughout the automotive industry. The choice of this method is ideal for parts of all complexities, and with the ability to provide a better than 2:1 high/low thickness distribution, this is an excellent choice for most applications.