Under heavy and medium load conditions, in addition to silver tungsten (AgW) contacts as important components, electrical switches can also use silver tungsten carbide electrical contacts as core components. Silver tungsten carbide(AgWC) electrical contacts have good electrical conductivity, excellent thermal conductivity, low and stable contact resistance, high corrosion resistance, strong resistance to welding, etc., so they are widely used in high-current switches. The specific steps of a high-performance silver tungsten carbide electrical contact preparation method are as follows:

First, a powder mixing process is used to obtain a uniformly mixed Ag and WC mixed powder consisting of raw silver powder and tungsten carbide powder; then a powder pressing process is used to press the mixed powder into a powder blank according to the required shape through molding; then a melt infiltration sintering process is used to place a prepared thin silver sheet on the powder blank, and send it into a sintering furnace (molybdenum wire sintering furnace), heated to a temperature higher than the melting point of silver, the silver sheet melts and infiltrates into the powder blank, and then a silver tungsten carbide electrical contact material is obtained; finally, a polishing process is used to beautify the surface of the silver tungsten carbide electrical contact material.

The precautions for this production technology are as follows:

1) Before using the infiltration sintering process, the surface of the blank needs to be treated, that is, colloidal graphite slurry is sprayed on the side of the powder blank where the silver tungsten carbide electric contact working surface will be generated, and then dried at low temperature to form a graphite layer.

2) The infiltration sintering process needs to be carried out in a reducing atmosphere such as hydrogen or vacuum atmosphere.

The advantages of this production technology include:

• By infiltrating silver into the silver tungsten carbide electric contact material matrix, the silver content reaches the standard, the conductivity of the electric contact material is improved, and the heat generation of the electric contact is reduced;
• By setting a graphite layer on the lower surface of the electric contact material matrix, silver can be prevented from penetrating the working surface, and contact welding occurs during the opening and closing of the moving and static contacts, ensuring the normal operation of the system.