The coating is actually a layer of protective film relative to the outer side of the protective connector. If there is no coating, the wire to board connector will be oxidized and corroded by the air. In fact, the role of coating is not only here, but also some other functions.

1. If there is coating, the connector is not easy to be oxidized, corroded and vulcanized.

2. If there is coating, the connector can also improve its mechanical properties to a certain extent, and increase the service life of the connector.

3. At the same time, it can also optimize the electrical performance of the connector, build and maintain stable connector impedance.

4. The noble metal coating is relatively simple for metal contact and maintains the stability of contact interface impedance.

5. What's more important is that there is a layer of oxide film on the surface of common metal coating, which ensures that the oxide film is damaged when the connector fits and that the contact interface is no longer oxidized.