Coating classification

Coating classification
According to the composition of the coating, it can be divided into three categories: single metal coating, alloy coating, and composite coating.
If classified by purpose, it can be divided into:
① Protective coating;
② Protective decorative coating;
③ Decorative coating;
④ Repair coating;
⑤ Functional coating
Single metal electroplating
Single metal electroplating has a history of over 170 years, and there are 33 metals on the periodic table that can be electrodeposited from aqueous solutions. More than 10 commonly used methods include electroplating, nickel, chromium, copper, tin, iron, cobalt, cadmium, lead, gold, silver, etc. The coating formed by simultaneously depositing two or more elements on the cathode is an alloy coating. Alloy coatings have organizational structures and properties that a single metal coating does not possess, such as amorphous Ni-P alloys, various Sn alloys that are not present in the phase diagram, and alloy coatings with special decorative appearances, particularly high corrosion resistance, excellent weldability, and magnetic properties.
Composite plating
Composite plating is the process of adding solid particles to the plating solution and co depositing with metals or alloys to form a metal based surface composite material to meet special application requirements. According to the electrochemical properties between the coating and the base metal, the electroplating layer can be divided into two categories: anodic coating and cathodic coating. When the potential of the coated metal relative to the base metal is negative, forming a corrosive micro battery, the coating is called an anode, hence it is called an anodic coating, such as the zinc coating on steel parts; The potential of the coated metal relative to the base metal is positive, and when forming a corrosive micro battery, the coating is the cathode, so it is called a cathodic coating, such as the nickel and tin plating layers on steel parts.

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