Metals

Electroplate

The principal function of electroplating is to make a cheaper metal look like silver. The physical properties of the materials are dominated by the underlying parent metal or alloy.

When an object is being electroplated, it becomes part of an electrolytic cell, as if it were part of a battery. The object is the negative electrode—that is—the cathode. The anode—or positive electrode—is usually made of pure silver. During the electroplating process, the object is placed in a solution containing silver salts—for example silver cyanide—and a direct, electrical current is passed through the object. As this happens, the object becomes coated with a layer of pure silver. At the anode, the silver is oxidised to produce silver ions, which replace the silver in the solution.

If an inert anode such as stainless steel or platinum is used, the bath would need regular replenishment of the silver salts, to keep the same operating conditions in the plating bath.

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If a silver/copper alloy layer is required, then the appropriate combination of silver and copper salts is dissolved, and the corresponding alloy is used as the anode.