Properties and application of copper coating:
Copper coating is a beautiful rose color, soft, malleable, easy to polish, and has good thermal conductivity and electrical conductivity. However, it is easy to oxidation in the air, thus rapidly losing luster, and therefore not suitable as a protective decorative coating layer.
Copper plated steel is mainly used for a multi-layer plating layer, the "bottom" is often used as a tin, gold and silver plated at the bottom layer, its role is to enhance the bonding force between the substrate and metal surface or coating, but also is beneficial to deposition of surface coating. When the copper coating has no hole, it can improve the corrosion resistance of the surface coating, such as the advantage of the thick copper thin nickel plating process in the protective decorative multilayer coating.
Properties and applications of nickel coatings:
Metal nickel has a very strong passivation ability, can quickly produce a thin layer of passivation film on the surface of the workpiece, can resist the atmosphere and some acid corrosion, so the stability of nickel coating in the air is very high. In the simple salt electrolyte of nickel, it is possible to obtain the extremely fine crystalline coating. The polished nickel coating has a mirror like luster, while maintaining its luster in the atmosphere for a long time. In addition, the nickel coating has high hardness and wear resistance. According to the properties of nickel coating, it is mainly used as the bottom layer, middle layer and surface layer of protective decorative coating, such as nickel chromium coating, nickel copper nickel chromium coating, copper nickel chromium coating and copper nickel coating.
Due to the high porosity of nickel coating, only when the thickness of the coating is more than 25 m, it is not porous, so nickel plating is generally used as a protective coating.The production of nickel coating is very large, and the amount of nickel consumed by nickel plating is about 10% of the total nickel production in the world.