1.Definition and scope of electrical contact materials:

“Electrical contact” is the process of transferring and converting current connecting or disconnecting in electrical power and load current appliances.In modern society, from the most ordinary household life to all industrial sectors, and even high-tech fields such as military industry, electrical contact processes are everywhere, such as connectors, micro switches, various small relays, potentiometers, micromotor brushes , the use process of electric slip rings, conductive commutators, vibration alternators, signal wheel brushes, various plug sockets, integrated circuit lead frames, printed circuit board sockets, etc.

According to the type of materials, they are mainly divided into four categories: copper-based electrical contact materials, silver-based electrical contact materials, gold-based electrical contact materials and new electrical contact materials. Electrical contact materials can be divided according to their application fields: electric contacts for light loads (electrical contacts with operating voltage less than 30V and current less than 60A), electric contacts for low-voltage electrical appliances (AC voltage less than 1,200V or DC voltage less than 1500V , current is 6-6300A, making and breaking current can reach 100kA. Electrical contacts in electrical appliances) and electrical contacts for medium and high-voltage electrical appliances (AC voltage greater than 1200V or DC voltage greater than 1500V)), among which low-voltage electrical appliances are electrical Main application areas of contact materials.

2. Performance requirements of electrical contact materials:

①Physical properties: low resistivity and vapor pressure, high thermal conductivity, melting point, boiling point, heat of fusion and heat of sublimation, as well as thermal stability, large heat capacity, and high electron work function to ensure high arc starting voltage and arc starting High current

②Mechanical properties: high strength and hardness at room temperature and high temperature, as well as good plasticity and toughness

③Electrical contact performance: resistant to arc burning damage, low and stable contact resistance, small tendency to welding and metal transfer

④Chemical properties: It has good corrosion resistance to a wide range of different media. It is not easy to oxidize, carbonize, sulfide, and form compounds or salt slag films that are not easily conductive in the atmosphere; it has high electrochemical potential and is resistant to chemical corrosion and gas dissolution. Little tendency

⑤Processing and manufacturing performance: It is required to be easily welded and fixed to the contact base and contact bridge by brazing or other methods.

3. Development trends of electrical contact materials:

Precious metals are the most widely used and reliable electrical contact materials due to their comprehensive and excellent properties unmatched by other metals, such as good electrical and thermal conductivity, electrical and thermal stability, excellent oxidation and corrosion resistance, and good machinability. In recent years, the high content of precious metals, mainly precious metals, has changed to low silver content of precious metals and a variety of inexpensive precious metal materials, to "miniaturization, superior performance, environmentally friendly materials, long life, high reliability", and more diversified fields of application.

——The content of the article comes from the Internet