ELECTRODES

The terminals by which electricity enters or leaves a solution or other conducting medium. The positive electrode which is the one by which the current enters the medium, is known as the anode, while the negative electrode is known as the kathode (sometimes spelt cathode). In the proce of electroplating, the article to be plated forms the kathode of the cell. For instance, a spoon to be plated with silver will be placed in a cell containing a solution of silver nitrate. One, or more, bars of silver are also placed in the solution and these bars and the spoon are connected to a battery in such a way that the current enters through the bars and leaves through the spoon. The bars thus become the anodes of the cell, while the spoon is the kathode. Within the cell, the current travels from the anode to the cathode, the solution of silver nitrate is split up and a layer of silver is deposited on the spoon. Elecodes are made of various materials according to the uses to which they are put. Anodes are commonly made of graphite, lead, iron alloys or platinum. Cathodes are commonly of metal, especially those used in refining, which are usually of the same material as the metal being deposited.