Electroplating 101

Electroplating is the process of depositing a thin layer of metal onto the surface of a base metal using electricity. Why would you do that? The additional layer protects the base metal from corrosion, reduces friction, makes the base metal stronger and more durable, promotes conductivity and solderability, or improves a part’s appearance. Electricity is used to make the surface layer adhere firmly to the base metal.

The anode (positive) is the name given to the metal that is to be deposited onto the base metal. The cathode (negative) is the name given to the base metal. For example, let’s say you had a steel part that you wanted to add a layer of zinc onto the surface. The steel would be the cathode and the zinc would be the anode. Both the anode and the cathode, the part and the metal to be attached on its surface, are placed into an “electrolyte bath.” The bath is carefully prepared to facilitate the transfer of metal ions electronically from the anode (such as zinc) to the cathode (the customer’s steel part).

A DC current takes metal ions from the anode and dissolves them into the bath. The cathode receives those metal ions from the bath and deposits them onto its surface.  For this process to work effectively, the following variables must be correct: cleaning, the electrical current, the temperature and chemistry of the bath, and the time in the tank. The industry has established specifications that guide a plating and finishing company to choose the right set of variables for each common process to be performed on a part.