The Process of Electrodeposition
The galvanic coating is an electrochemical processing method. By means of direct electrical current, nickel is dissolved in an anodic reaction and deposited in a cathodic reaction as pure nickel on a substrate.
anodic reaction: Ni ---> Ni2+ + 2 e-
cathodic reaction: Ni2+ + 2 e- ---> Ni
The electrical current functions as a "pump" for the electrons. This process runs only in a solution of liquid electrolyte.
A permanent electrodeposition of nickel on a substrate with a thickness of more than 0,1 mm is defined as electroplating or thick nickel plating.
A non-permanent thick nickel plating (more than 3 mm) where the coating is separated from the metal surface is defined as electroforming.
During the electroforming process, nickel or other metal in solution is electroplated onto a mandrel in order to reproduce the pattern on the mandrel's surface with up to some nanometers. Although gold, silver and copper can all be electroformed, nickel is the metal of choice because it is versatile, resists heat, corrosion and abrasion, and can be electro-deposited quickly.