Did you ever wonder how a hinge or small screw got completely coated in zinc or brass? You could take these parts and dip them in molten metal, but the coating is uneven, and you do not get a thin coating this way. It is more efficient and easier to use a method like zinc nickel electroplating. Here is how the process works and some reasons why it is so popular.
Plating with Chemistry and Electricity
If you place metal in an acidic solution and add an electric current to another metal, atoms get unbalanced and turn into ions. As negative and positive ions attract each other, you get a coating on metal. For example, positive copper pennies attach themselves to negatively charged iron material. This forms a thin and even coating of copper on the iron thanks to the power of electricity.
This is a simplified explanation of the process. In an industrial zinc nickel electroplating processes, an anode made of a zinc nickel alloy receives a charge from DC current. Items for plating get placed in a bath or solution containing cyanide or other ingredients. This provides chemical as well as electrical reactions to coat the metal parts.
Methods
Two of the most common methods for zinc nickel electroplating are barrel and rack plating. With a barrel plating method, parts get placed inside of a revolving drum or barrel as they get electroplated. Rack plating uses large racks dipped in electroplating solution as a current passes through them. Barrel plating is best for many small parts, and rack plating is often used for larger and more complex parts.
Benefits
Plating parts with a zinc nickel alloy make them resistant to rust and corrosion. It reduces wear on parts and can increase electrical conductivity. The process creates a smooth and even finish.
