Failure of silver contact refers to the silver contact in the process of use because the contact surface resistance increases, so that the function of the silver contact is abnormal, which may be composed of the following factors:

vulcanization

Because silver easily reacts with sulfur, silver sulfide is formed. It is assumed that there are rubber bands, sulfur-containing corrugated paper, sulfur-containing label paper, dry tape, rubber pads, rubber tires, sulfur gas, etc. in the use environment, which will cause silver contacts to become black. At the same time, due to the increase of ambient temperature, the vulcanization rate can be increased.

Dust pollution

Air dust will adhere to the outside of the silver contact.

Acid corrosion

Silver contacts treated with nitric acid leaching and electroplating techniques will wash away the outer surface of the silver alloy and expose the metal to air to form metal oxides. Part of the battery phenomenon: also known as microcell. Many fine short-circuited primary cells consist of a thin film of metal, such as carbon or other metal particles, and are covered with an electrolyte solution.

Assuming that the base metal is more reactive than the impurities, the metal dissolves and electrochemical corrosion occurs.

For example, the appearance of a metal machine is exposed to humid air, absorbing carbon dioxide and water vapor in the air to condense on its appearance, becoming an electrolyte solution that forms part of the battery and causes mechanical corrosion.

Other pollution

Substances such as automobile exhaust, dust, sweat, grease, cleaners, polishes, etc., will also make silver contacts ineffective when carbon dioxide is used at high temperatures during switch use.