The pros and cons of electric contact material performance is affecting the service life of vacuum switch equipment operating characteristics and the electricity one of the key factors. Early vacuum switch almost all adopt w.M o refractory metals, such as contact materials. Contact materials such as a series of advantages, such as there is proper breaking capacity, good compressive strength and resistance to fusion welding, the appropriate heat transfer coefficient and electrical conductivity, the arc ablation rate is small, contact the service life is long, etc., until now has been widely used in vacuum switch breaking small current. But high melting point of pure metal contact material has many shortcomings, such as breaking current and high level of river closure, therebyLimit the use of vacuum switch range
Using high conductive thermal conductivity of pure metals such as cu as vacuum contactor material, although has the good breaking large current capacity, and have quite a good voltage resistance, intercepting level is low, but can't resist fusion welding. To overcome this defect, 40 to 50 s development represented by Cu - Bi binary high conductive and low melting point alloy. Department of alloy significant disadvantage is high vapor pressure. Although it is good to limit level of river closure, but after current zero medium restore slower, easy cause gap breakdown. Other contact burning speed, short service life of contacts. 60 s, the electric company Robinson, the first put forward by Cu, Cr instead of at that time has been widely used in Cu - Bi alloy. Because he found that compared with Cu - Cu - Cr Bi material has a higher ability to withstand voltage, arc erosion resistance and open circuit performance.
In his adopted caused high Ni part is contained in the manufacturing process of high resistivity. After the 10With years of effort by the mid - 80 - s, Cu, cr contact material to the operation characteristics and mechanism, its superior performance, gradually accepted by the designers, using the contact material producing and commercial vacuum arcing chamber is also more and more. After the 90 s, cu, Cr has become a widely adopted medium-voltage high-power vacuum arcing chamber contact materials [2]. 2 vacuum contactor material performance requirements
