Abstract: A vacuum valve includes a hermetically sealed vessel having an insulative cylinder, an end plate at a movable electrode end, and an end plate at a fixed electrode end. The vessel accommodates a movable contact and an opposed fixed contact. The movable contact is supported through a bellows allowing the contacts to open and close while maintaining an air-tight (hermetic) seal. The bellows used in at least one embodiment is a seam type bellows without metal plating. Nickel plating layers are formed on the end plate at movable contact end and on a cover, which are joined to the bellows. The ends of the bellows are soldered with the end plate and the cover using a silver solder at the solder joints.

Abstract: A vacuum valve includes a hermetically sealed vessel having an insulative cylinder, an end plate at a movable electrode end, and an end plate at a fixed electrode end. The vessel accommodates a movable contact and an opposed fixed contact. The movable contact is supported through a bellows allowing the contacts to open and close while maintaining an air-tight (hermetic) seal. The bellows used in at least one embodiment is a seam type bellows without metal plating. Nickel plating layers are formed on the end plate at movable contact end and on a cover, which are joined to the bellows. The ends of the bellows are soldered with the end plate and the cover using a silver solder at the solder joints.

Abstract: Interrupting and chopping characteristics of a Cu--Cr contact alloy are improved by rounding Cr particles to be spherical in the alloy. The Cr particles are rounded in the alloy by sintering raw Cr powder particles having an average particle diameter of less than 100 .mu.m at a temperature of 1,100.degree. C. or higher with Cu powder, or by sintering raw Cr powder particles having an average particle diameter of 100 to 150 .mu.m at a temperature of 1,200.degree. C. or higher with Cu powder.