Vacuum interrupter and vacuum switch thereof

Abstract

{W—Cu Sb-balance Cu} alloy is employed for contacts. As the anti-arcing constituent in the alloy W or WMo in a content of 65 to 85%, of grain diameter 0.4 to 9 &mgr;m is employed. As auxiliary constituent, Cu Sb is employed, the content of the Cu Sb being 0.09 to 1.4 weight %, the x being x=1.9 to 5.5, the grain diameter being 0.02 to 20 &mgr;m, and the mean distance between grains being 0.2 to 300 &mgr;m. As conductive constituent, Cu or CuSb solid solution is employed, the Sb content present in solid solution form in the CuSb solid solution being less than 0.5%. As a result, not only is dispersion of Cu Sb, which is evaporated on subjection to arcing, reduced, but also generation of severe cracks, which have an adverse effect in terms of occurrence of restriking. Arcing at the contacts surfaces is prevented, suppressing dispersion and exfoliation of W grains. In this way, damage due to melting and dispersion at the contacts surfaces is reduced, enabling both restriking to be prevented and the contact resistance characteristic to be improved.