Electroplating is the process of plating a thin layer of other metal or alloy on certain metal surfaces using electrolysis. It has a single metal coating, an alloy coating and a composite coating. It is protective, decorative, repairable and functional on metal surfaces.
Single metal plating has been more than 170 years old, and 33 metals on the periodic table have been electrodeposited from aqueous solutions. Commonly used are electroplated zinc, nickel, chromium, copper, tin, iron, cobalt, cadmium, lead, gold, silver and other more than 10 kinds. A plating layer formed by simultaneously depositing two or more elements on the cathode is an alloy plating layer. The alloy coating has the structure and properties not possessed by a single metal plating, such as amorphous Ni— P alloy, each of the Sn alloys not on the phase diagram, and has a special decorative appearance, particularly high corrosion resistance and excellent weldability. , magnetic alloy plating, etc.
Composite plating is the process of adding solid particles to a bath to co-deposit with a metal or alloy to form a metal-based surface composite to meet specific application requirements. According to the electrochemical properties between the coating and the base metal, the plating layer can be divided into two types: anodized coating and cathodic coating. Where the potential of the plated metal relative to the base metal is negative, the plating is an anode when the microbattery is formed,
Therefore, it is called anodized coating, such as galvanized layer on steel parts; and the potential of plating metal relative to the base metal is positive, when the corrosion of micro-battery is formed as the cathode, it is called cathodic coating, such as steel parts Nickel plating and tin plating on the top.