There are many different options to choose from in electroplating including several different zinc alloy options. Zinc nickel plating is considered one of the best options and the superior choice for use on many parts and components in the automotive and aerospace industries.
One of the biggest benefits of zinc nickel plating is the extremely high corrosion resistance provided. The estimated salt spray results to white rust is approximately three hundred and sixty hours with at least a thousand hours to red rust. In addition, even with high thermal shock of 120° C or 250°F for 24 hours, the corrosion resistance is still dependable at those high levels. However, generally this process is not recommended for any parts requiring additional forming after the plating process.
The Look
While not directly related to part performance and durability, there is another major benefit to zinc nickel plating over other options. It creates a surface look which is uniformly bright and looks very much like stainless steel, which is important in both automotive and aerospace industrial applications.
It is also capable and will readily accept trivalent passivates, which can be in either clear or black, adding to the options for manufacturers to consider. This additional passivate process provides additional level of protection from corrosion and white rust.
The Process
Adding to the popularity of zinc nickel plating is the versatile options for this type of plating. It can be electroplated using rack plating or barrel plating techniques. Rack plating is typically used for more detailed parts with threads or smaller pieces which may not be appropriate for the barrel technique. In rack plating the parts are mounted to a rack, or jig, and then plated and removed.
In barrel plating the parts are placed in larger quantities in the compartment, known as a barrel. There is limited need to work manually with the parts making this a faster and more economical option for zinc nickel plating than rack plating or wiring. While barrel plating is faster and easier, rack plating provides better salt spray results and better overall corrosion resistance because of the slightly higher standards required.
When corrosion resistance, high performance and a uniform look in the plating is a priority for any parts, zinc nickel plating is the most recommended option. Choosing between rack plating and barrel plating is then a determination based on the part size, type and which process is best suited for the specific project.
