Electroplating is basically the process of electroplating a metal onto another metal by hydrolysis, mainly to prevent the metal from corroding or for decorative purposes. The process uses an electric current to reduce dissolved metal cations, resulting in a thin, coherent metal coating on the electrode. Electroplating is typically applied to the electro-oxidation of anions on solid substrates, such as the formation of silver chloride on silver wires to form silver chloride electrodes.
Electroplating is primarily used to alter surface characteristics of objects (e.g. corrosion protection, lubrication, wear), but the process can also be used to increase thickness or to manufacture objects by electroforming.
Anode and Cathode
In electroplating practice, electrical current is usually introduced from an external source, with the anode being the positive and the cathode being the negative. The cathode is the electrode where the electrochemical reduction reaction occurs. The anode is where the electrochemical oxidation reaction takes place.
The electroplating process uses anodes and cathodes. In electroplating, metal dissolved from the anode can be plated onto the cathode. Direct current is applied to the anode, which oxidizes and dissolves its metal atoms in the electrolyte. At the cathode, dissolved metal ions are reduced and the metal is deposited on the product.
How does electroplating work?
To understand this concept further, let's take a gold coating as an example. In this case, a layer of gold will be plated on the metal jewelry to enhance its appearance.
Typically, the gold plating is connected to the anode (+ve charging electrode) of the circuit, while the jewelry remains at the cathode (-ve charging electrode). Both are immersed in a highly developed electrolytic rod (solution). At this stage, a DC current is supplied to the anode, oxidizing the gold atoms and dissolving them into solution.
The dissolved gold ions are reduced at the cathode and plated on the jewelry.
However, there are many main factors that affect the final plating. These include:
The voltage level of the current.
The temperature and chemical composition of the bath.
The current length of time.
distance between cathode and anode.
The use of electroplating
When it comes to the uses of electroplating, it is used for various other purposes besides enhancing the appearance of the substrate. The main application is to optimize the corrosion resistance of materials. The plating is often used as a sacrificial coating, indicating that it dissolves before the base. Some other common applications for electroplating include:
Improve wear resistance.
Increase the thickness of the metal surface.
Enhanced conductivity, such as copper plating on electrical components.
Improve surface uniformity.