Provided are: a method for producing an
electrode material for a vacuum
circuit breaker, whereby withstand
voltage,
high current interruption performance and
capacitor switching performance can be improved; an
electrode material for a vacuum
circuit breaker; and an
electrode for a vacuum
circuit breaker.The
electrode material for a vacuum circuit breaker is produced by a method comprising a mixing step, a press
sintering step, and a Cu infiltration step. In the mixing step, an Mo
powder having a particle
diameter of 0.8 to 6 μm is homogeneously mixed with a
thermite Cr
powder having a particle
diameter of 40 to 300 gm in such a manner as giving a
mixing ratio (Mo:Cr) of 1:1 to 9:1 and satisfying the weight relation Mo≧Cr. In the press
sintering step, the
resultant mixture is pressure molded under a press pressure of 1 to 4 t / cm2 to give a molded article. Next, said molded article is sintered by maintaining the same at a temperature of 1100 to 1200° C. for 1 to 2 hours in an
heating furnace to give a partially sintered article. In the Cu infiltration step, a thin Cu plate is placed on said partially sintered article and maintained at a temperature of 1100 to 1200° C. for 1-2 hours in a
heating furnace so that Cu is liquid-phase sintered and infiltrated into the partially sintered article. A contact material of an electrode for a vacuum circuit breaker has an integral structure consisting of a central member and a Cu—Cr outer
peripheral member, said central member having been produced as described above and comprising 30 to 50 wt % of Cu of a particle
diameter of 20 to 150 μm and 50 to 70 wt % of Mo—Cr of a particle diameter of 1 to 5 μm, while said outer
peripheral member being formed of a material, which is highly compatible with the central member, shows excellent interruption performance and had high withstand
voltage, and being provided outside the central member and fixed thereto.