Electroplating is a process of metal coating through electrolysis. Electrolysis is passing of an electric current through an electrolyte solution. In other words, it is the process to cover a metal with a thin coating of another metal either for protection against corrosion or for beautification of house hold items. The electroplating may also be used to impart certain other properties to a metal surface, such as hardness, wear resistance and anti-frictional, electrical, magnetic or optional properties. Do you know how metals are electroplated?

               Electroplating is done in large vats containing a solution of some suitable salt of the metal to be coated. Bars or plates of metal are used as anode, and are arranged inside the vats. This metal body, called the work piece, makes the cathode. When the electric current is passed through the solution, by connecting the positive terminal of the battery to the anode and negative terminal to the cathode, the metal ions from the solution go towards the cathode and get deposited on the work piece and form a thin layer of metal on it. The metal from the anode goes on dissolving in the solution and finally gets deposited on the work piece.

               To ensure an even deposit, the work piece may be slowly rotated inside the vat. The surface to the work piece must be clean and free from grease, dirt or oxide films. These days the metals that are electroplated include silver, gold, nickel, copper and chromium. For silver plating, double cyanides of potassium and silver are used. The silver plating is usually done on brass table-wares such as spoons, forks and other utensils. It is also done on ornaments. The gold baths also contain double cyanides of gold and potassium. This plating is also done on ornaments. The nickel plating baths involve double sulphates of nickel and ammonium. The copper bath contains a solution of copper sulphate with small quantities of sulphuric acid. The chromium plating is done by using the solutions of chromic acid and chromic sulphate with small quantities of chromium carbonate usually used on machine parts.

               The other metals which are electroplated commercially include cadmium, cobalt, platinum, rhodium, tin, zinc, etc. In certain cases two or more metals are plated simultaneously as alloy coatings, e.g. copper-zinc, copper-tin, lead-tin, lead-tin-copper, tin-nickel and nickel-cobalt.