Electroplating:
– It is the process of providing metallic coating by means of electrolysis. Both the metals and non –metals can be coated by this process. The surfaces to be electroplated should be cleaned properly.
– This process consists of an electrolyte, an anode (+ve terminal) and a cathode (-ve terminal). A low voltage d.c. supply is provided to the circuit.
– An electrolyte is a dissolved salt of the plating material. The workpiece to be coated or plated acts as cathode i.e. connected to negative terminal. The material to be deposited acts as anode i.e. connected to positive terminal.
– The ions carry the +ve charge from the anode and move towards –ve charged metal (cathode). They lose their charge and deposit on the cathode as metal.
– Most commonly used alloys and metals, which are used as plating material, include Copper, Zinc, nickel, chromium, platinum, gold, brass, silver etc.
– Following types of electrolytes are used in electroplating
Acid bath – Provides a heavy layer of coating with a very good finish. It is most commonly used.
Alkaline bath – Provides a very smooth finish having dense and fine grains.
Neutral bath – Used normally for the plating of nickel