Brass plating is the most widespread alloy plating method due to its color and decorative outlook. Applications vary from fastners, lighters, and fittings to other hardware and even functional applications such as corrosion-resistant coatings in marine environments. Usually, brass plating is post-treated with lacquer to prevent any tarnishing or discoloration.
A brass-plating process is done mainly from cynide solution. The solution contains a mixture of copper and zinc cyanides, although zinc can exist in other forms as well. The amount of the bath constituents can vary in great amounts. The copper to zinc ratio is the most important parameter to control the deposit composition, which is typically held at about 4:1. The free cyanide and pH affect the color of the deposit and coating uniformity. Ammonia can be used to enhance the throwing power and color of the coating. Organic or metallic brightner are used to increase brightness and improve grain refinement. Tartrates or citrates are used to prevent anode polarization.