Electroplating on the surface of the terminal is a technical method to solve the oxidation and corrosion of the metal on the surface of the terminal, enhance the conductivity of the terminal, and reduce the contact resistance. Besides gold, silver, and nickel or chrome plating, tin plating is most commonly used in terminal plating.
Gold itself has high chemical stability, strong corrosion resistance, high temperature resistance, easy welding, strong electrical conductivity, and certain wear resistance. However, it is also expensive due to the metal used in the cathode coating. Because the gold plating layer is thin and the process is not in place, some microporous corrosion of the plating layer has occurred in actual production, which affects the protection performance. Therefore, it is often used in the terminal connection part to reduce the contact resistance of the connection.
Silver itself has high chemical stability, is not easy to corrode in the air, has good welding performance, and has good electrical and thermal conductivity. But its disadvantage is that it will be halogenated or vulcanized when exposed to air containing halides and sulfides, the surface of the silver plating layer will change color, and the conductivity will decrease. Moreover, microporous corrosion will occur when it is wet, so it is generally used in terminal connections similar to gold to reduce the contact resistance of the connection.
Tin has stable chemical properties, strong ductility, and is not easy to change color in the atmosphere. And because the tin coating is soft, it can improve the running-in of mechanical sliding parts. Therefore, tin plating can improve solderability and prevent nitriding. It is often used in electronic products and is a common terminal plating process.
In addition, there are nickel and chrome plating. When the thickness of the nickel coating is less than 25 microns, there are many pores, and the solderability of the nickel coating becomes poor due to passivation. Chromium plating has good hardness, wear resistance and heat resistance. Chrome plating is mainly used for decorative plating and functional aspects.
As can be seen, the terminals have various platings. Generally, the plating of the crimping part of the terminal is tin-plated, and the plating of the connecting part of the plug-in terminal is gold-plated, silver-plated or multi-layer plated. Determine the required plating according to the requirements of the terminal.

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