Electroplating is the process of electrolytically plating a metal with a thin layer of another metal to improve the corrosion resistance of the metal.
Metals commonly used in electroplating are:
copper
nickel
the gold
silver
chrome alloy
zinc
tin
Electroplating is also known as electrodeposition and electroplating coating.
The main purpose of electroplating is to improve:
appearance
Corrosion protection
special surface properties
engineering or mechanical properties
During electroplating, the anode is connected to the positive electrode and the cathode (the metal being plated) is connected to the negative electrode. Both are immersed in a solution containing electrolytes and then connected to an external DC power source. When a direct current is applied, the anode is oxidized -- its metal atoms dissolve in the electrolyte solution. These dissolved metal ions are reduced at the cathode and form a coating. The current through the circuit is adjusted so that the rate at which the anode dissolves equals the rate at which the cathode deposits.
Different metals can be coated using the electroplating process. Preparation of the correct electrolyte is very important to the quality of electroplating.
Electrolytes used in this process include:
acid
base
metal salt
molten salt
Electrolyte properties to consider for selection are:
Corrosive
resist
brightness or reflectivity
hardness
Mechanical strength
Extensibility
wear resistance
