Detailed explanation of the properties and uses of copper and nickel coatings on PCB multilayer boards

   1. Performance and application of copper plating on multi-layer printed circuit boards:

The copper coating on the PCB multi-layer board has a beautiful rose color, is soft, ductile, easy to polish, and has good thermal and electrical conductivity. But it is prone to oxidation in the air, so it quickly loses its luster and is not suitable as a "surface layer" for protective decorative coatings.

The copper coating on PCB multilayer boards is mainly used as the "bottom layer" for multi-layer electroplating of steel parts, and is also often used as aTin plated, gold plated, silver plated'Bottom layer'. Its function is to improve the adhesion between the base metal and the surface or (or intermediate) coating, and also facilitate the deposition of surface coatings. When the copper coating on the multi-layer printed circuit board has no holes, the corrosion resistance of the surface coating can be improved. For example, the multi-layer plating process of protective decoration with thick copper and thin nickel has the advantage of saving precious metal nickel.

    2. Performance and application of nickel plating on multi-layer boards

Nickel has strong passivation ability, which can quickly form an extremely thin passivation film on the surface of the workpiece and resist the corrosion of the atmosphere and certain acids. Therefore, the nickel coating of PCB multilayer boards has high stability in air. In a simple salt electrolyte of nickel, a coating with extremely fine crystals can be obtained, which has excellent polishing performance. The polished nickel coating on PCB multi-layer boards has a mirror like luster and can maintain its luster for a long time in the atmosphere. In addition, the nickel plating layer on PCB multilayer boards also has high hardness and wear resistance. According to the properties of nickel plating on PCB multilayer boards, it is mainly used as the bottom layer, middle layer, and surface layer of protective decorative coatings, such as nickel chromium coatings, nickel copper nickel chromium coatings, copper nickel chromium coatings, and copper PCB multilayer board nickel plating.

Due to the high porosity of nickel plating on PCB multilayer boards, it is only non porous when the plating thickness is above 25m, so nickel plating is generally not used as a protective coating.

The production of nickel plating on PCB multi-layer boards is large, and the consumption of nickel plating accounts for about 10% of the world's total nickel production