What is the difference between copper plating nickel and copper plating tin? FUNCTION: All kinds of coating have a common advantage of anti-corrosion (improve anti-oxidation ability) , play a decorative role. COPPER-NICKEL PLATING: After plating in the atmosphere and Lye chemical stability is good, not easy to change color, more than 600 degrees Celsius was oxidized, high hardness, easy polishing, the disadvantage is porous, nickel plating surface looks a little bright, it feels smooth to the touch. There is a strong adhesion and wear resistance. Copper Tin Plating: high chemical stability, in sulfuric acid, nitric acid, hydrochloric acid in dilute solution almost insoluble, good welding performance. Tin Plating protects against electromagnetic interference. The tinned ones look white, not so pretty, and there's a dark gray layer of foam when you touch them. Use: according to the use of different occasions, to choose nickel or tin plating process. 1. If it is the appearance of components, generally more choice of nickel-plated, smooth and good-looking, high-temperature experiment after color. 2. If is requests the electric conduction ability to be strong, then the copper row surface uses the tin plating process. 3. If it is the internal components, such as PCB EMI shielding cover, are the choice of tin (barrel plating) , some of the first layer after nickel plating tin. The following is the copper row before and after tinning and nickel conductivity changes in comparison test: 1. Before and after Tin Plating Copper Bar test: figure 1: Copper Bar Tin before the conductivity of 98.6% iacs

Fig. 2: The conductivity of Copper Strip after tin plating is more than 98.6% IACS, which is slightly higher than that before tin plating

2. Test of conductivity change before and after nickel plating on copper strip: 3. Fig. 3: Conductivity of iacs is 98.6% before nickel plating

Fig. 4: The conductivity of iacs is 75.8% after nickel plating, which is 22.8% lower than that before tin plating

The test results show that the electrical conductivity of the copper strip increases slightly after tin-plating on the surface of the copper strip when the two samples are the same, after nickel plating on the surface of copper strip, the conductivity of iacs is reduced by 22.8% , that is, the conductivity of iacs is reduced by 23% . Therefore, it is strongly recommended that the surface of red copper bar be tinned. If you have to choose a better brightness of the nickel plating process, then the copper row must be reduced capacity to use. 

Source: The web