The nickel plating process produces a silver-white deposit that is used for both engineering and decorative applications. It can be applied with a matte, sulfur-free appearance, semi-bright, or mirror bright finish by controlling the composition and operating parameters of the plating solution. The hardness of the nickel plate can also be varied from 150 to 500 Vickers, it has a low coefficient of thermal expansion and nickel is magnetic. For all these reasons, nickel is used in a wide variety of industries including automotive, appliances, hardware, plumbing, jewelry, aerospace, defense, and circuit boards. In decorative applications, nickel has an ability to cover imperfections in the base metal; this is referred to as leveling. As an undercoat for silver or chrome plating, the nickel will maintain its luster even under the severest conditions and it also works as a barrier against corrosion of the
Nickel is also used for engineering purposes. Its deposit offers more wearability than softer metals such as copper, brass, and zinc and can be used when wear resistance is needed, such as on molds. And since nickel can be made to plate with little or no stress it is used for electroforming.
There are a variety of nickel baths. The most commonly used is a Watts bath which uses a combination of nickel sulfate and nickel chloride. This combination of nickel salts allows it to
be used for a variety of characteristics and purposes. Other types of baths include chloride, fluoborate and sulfamate, each with its own advantages for different applications. Typical specifications for nickel plating include QQ-N-290 and ASTM B689