Establishing and maintaining a stable pin and female impedance is part of the electrical performance requirements of the pin and female. In order to achieve this goal, it is necessary to provide the inherent stability of the metal contact interface. To establish such a contact interface, the surface film must be avoided or split during contact and mating. These two different choices clarify the difference between precious metals or rare metals and ordinary metals.

    2. To a certain extent, the essence of precious metal coatings (alloys such as gold and palladium) is a free surface film.

        The metal contact of the interface produced by the coating is relatively simple, because only the companions of the contact surface need to move during mating. Usually this is easy to implement. In order to maintain the stability of the impedance of the contact interface, the design of the pin header should pay attention to maintaining the noble metal properties of the contact surface and prevent the influence of external factors such as the diffusion of pollutants, base metal, and contact wear.

    3. Ordinary metal coatings, especially tin and tin alloys, naturally cover oxide films.

        The role of the tin contact plating layer is that this oxide is easily destroyed when it is combined, and the metal contact is easily established. The requirement of the pin header design is to ensure that the oxide film is broken when the pin header is mated, and the contact interface will not be oxidized during the effective period of the electrical connection actuator. Re-oxidation corrosion is the most important performance degradation mechanism of tin contact plating in wear corrosion. The silver contact plating of the header and the female is best used as the common metal plating. Because this coating is easily corroded by sulfides and chlorides. The formation of the valve material usually also uses nickel plating as a common metal.