What is Involved in Nickel Electroplating?
Nickel electroplating is the process of coating an item with a layer of nickel by means of electrical material deposition. The process involves suspending the item and a nickel anode in a bath of electroplating solution and passing an electric current between the two. This causes a transfer of nickel metal particles between the bath and the recipient item. These particles bond with the recipient item at an atomic level, thereby coating it with a layer of nickel. The expended nickel bath content is replaced by particles from the anode which are shed into the solution during the electroplating process.
Electroplating is a very common material deposition method used to coat millions of tons of goods with a multitude of different metals every year. Nickel is one of the more popular plating metals with several attractive and beneficial characteristics. These include increased resistance to wear in softer metal parts, exceptionally low friction coefficients, and outstanding corrosion resistance. Nickel electroplating is also a popular decorative process that lends plated items a deep, lustrous shine. These decorative coatings include black nickel finishes and are available in a variety of brightness grades ranging from semi-bright to satin.
The nickel electroplating process is similar to most electrical material deposition methods. The recipient items are suspended along with a nickel anode in a bath of nickel electroplating solution. These are typically nickel/sulfate-chloride, nickel/fluoborate, or nickel/sulfamate mixtures for regular coatings and nickel sulfate/ammonium chloride/boric acid mixes used for hard coatings. A electric current is then passed between the nickel anode and the recipient items. In this process, the recipient parts act as a cathode or negative point, the anode the positive point, and the bath solution the conductive path in the circuit.
The flow of current from the anode to the plating items causes nickel particles in the bath solution to be attracted to the surface of the plating items. These particles bond atomically with the recipient surface, thus effectively causing a layer of nickel to “grow” on them. As this occurs, nickel particles are shed from the anode into the solution, thereby replacing those deposited on the plated items. The bath solutions are typically heated to between 100°-160° Fahrenheit (about 38°-71° Celsius) depending on which solution is used; each type of solution produces different tensile strength and hardness characteristics. The thickness of nickel electroplating coatings may be carefully controlled by manipulating the duration of the process, the cathodic efficiency coefficient, and the electric current.
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