Properties and applications of copper deposits:
Copper coating is a beautiful rose color, soft, malleable, easy to polish, and has good thermal conductivity and conductivity. But it is easy to oxidize in air, thus rapidly losing luster, and therefore not suitable as the surface of protective or decorative coating.
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, for example, in the protective decorative multilayer plating, the advantages of adopting the thick copper and thin nickel plating technology is that it can save precious metal nickel.
Properties and applications of nickel deposits:
Nickel metal has a strong passivation ability, and can be rapidly formed on the surface of a layer of extremely thin passivation film, can resist the atmosphere and some acid corrosion, so nickel coating in the air stability is very high. In the simple electrolyte of nickel, fine crystalline coating can be obtained with excellent polishing properties. The polished nickel coating has a mirror like sheen and can be maintained in the atmosphere for a long time. In addition, nickel coating also has higher hardness and wear resistance. According to the nature of nickel coating, it is mainly used as protective coating layer, interlayer and surface layer of decorative coating.
Because the porosity of nickel coating is higher, it is only when the coating thickness is above 25 um that it is nonporous. Therefore, nickel coating is not usually used as protective coating.
The amount of nickel consumed by nickel plating accounts for about 10% of the total nickel output in the world.