Abstract: 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 ?m 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.

Abstract: Atomized Cu—Cr alloy powder, 20 to 30 percent by weight of Thermite Cr powder and 5 percent by weight of electrolytic Cu powder are mixed together and undergo solid phase sintering treatment to form an electrode material for vacuum circuit breakers. The gross content of Cr of the electrode material is 30 to 50 percent by weight. In manufacturing the electrode material for vacuum circuit breakers, such powders are mixed together and then undergo compression molding to be formed into a compressed compact. The compressed compact is performed solid phase sintering at a temperature lower than the melting point of Cu in a non-oxidizing atmosphere to prepare a solid phase sintered body.

Abstract: Vacuum circuit breakers are to gain an extended lifetime by reducing contact face damage of moving and fixed electrodes with improved voltage withstand performance therebetween and enhanced interruption performance. Vacuum circuit breaker of the present invention has bulb 10 having: insulative vacuum tube 11; and fixed electrode 12 on end of current-carrying conductor 13 and moving electrode 15 on end of another current-carrying conductor 16 arranged in insulative vacuum tube 11 with their electrode contact faces opposed each other. Operation system for manipulating current-carrying conductor 16 of moving electrode 15 is equipped with compression-spring 20 and auxiliary compression-spring 21 that increases initial opening speed of moving electrode 15. Auxiliary compression-spring 21 ceases energizing in the middle of a circuit breaking movement of moving electrode 15 and begins storing spring energy in the middle of a circuit closing movement of the same.