Plating and metal finishing use nickel primarily as chemicals or nickel anode. In these end uses, the nickel is not part of an alloy system but is plated out as metallic nickel from soluble nickel in the plating bath. Chromium-nickel electroplating is by far the largest end use with substrates including steel, aluminum, plastic and zinc die-cast parts. Nickel possesses excellent plating properties and is consequently widely used for coatings, both for decorative and engineering applications. In most cases, the color, brightness or hardness of nickel plate can be changed by means of a decorative finish coat such as chromium.
Plated parts can be considered to be metal coated parts. European ELV restrictions (Directive 2000/53/EC) on the amount of hexavalent chromium do not apply to chromium in the metallic state which would be found in chromium-nickel plated parts.
Although nickel is used to produce electroformed plastic parts molds and electroless nickel is used to enhance the corrosion-resistance, wear resistance and lubricity of some parts, by far the largest application is for the production of bright finishes on parts such as bumpers, wheels and grilles. For exterior applications, these finishes would typically consist of 30 microns of nickel and 0.3 microns of chromium. Chromium-nickel plated parts are primarily employed for aesthetic design considerations, although durability and corrosion resistant characteristics are also important.
Currently, demand for nickel and chromium-nickel plated "brightwork" - wheels, bumpers, grilles and other trim - is quite strong, particularly in North America and the Far East. One reason for the resurgence of demand is the higher quality products now available.
Nickel Institute has produced a series of technical publications on electroplating and electroforming:
Other sources of plating information: