Properties and Uses of PCB Copper Plating and Nickel Plating

1. Properties and uses of copper plating:

The copper plating layer of PCB board is beautiful rosy, soft, malleable, easy to polish, and has good thermal and electrical conductivity. However, it is easy to oxidize in the air and lose its luster quickly, so it is not suitable as the “surface” layer of protective-decorative coating.

Copper plating is mainly used as the “bottom” layer in the multi-layer plating of steel parts, and it is also often used as the “bottom” layer in tin plating, gold plating and silver plating. Its function is to improve the bonding force between the base metal and the surface or (or intermediate) coating, and it is also conducive to the deposition of the surface coating. When the copper plating layer is non-porous, the corrosion resistance of the surface plating layer can be improved. For example, the advantage of the thick copper and thin nickel plating process in the protective-decorative multilayer plating is that it can save precious metal nickel.

2. The properties and uses of nickel plating:

Metal nickel has a strong passivation ability, which can quickly form a very thin passivation film on the surface of the part, which can resist the corrosion of the atmosphere and certain acids, so the stability of the nickel coating in the air is very high. In the simple salt electrolyte of nickel, a very fine crystalline coating can be obtained, which has excellent polishing performance. The polished nickel coating has a mirror-like luster while maintaining its luster for a long time in the atmosphere. In addition, the nickel plating layer also has higher hardness and wear resistance. According to the properties of nickel plating, it is mainly used as the bottom layer, middle layer and surface layer of protective-decorative plating, such as nickel-chromium plating, nickel-copper-nickel-chromium plating, copper-nickel-chromium plating and copper-nickel plating and so on.

Due to the high porosity of the nickel plating layer, it is non-porous only when the thickness of the plating layer is more than 25μm. Therefore, the nickel plating layer is generally not used as a protective plating layer.

The production of nickel plating is very large, and the amount of nickel consumed by nickel plating accounts for about 10% of the total nickel production in the world.