A method for producing an electrode material, involving: (i) a step of preparing a powder of a solid solution of Cr and a heat resistant material selected from the group consisting of Mo, W, Ta, Nb, V and Zr, wherein either a peak corresponding to Cr element or a peak corresponding to the heat resistant element, which are observed by X ray diffraction measurement made on the powder of the solid solution, disappears; (ii) a step of molding the powder of the solid solution to obtain a molded body and then sintering the molded body to produce a sintered body; and (iii) a Cu infiltration step of infiltrating the sintered body with Cu.

A contact assembly for a vacuum switching apparatus includes a contact member and a reinforcing member adapted to structurally reinforce the contact member. The contact member includes first and second opposing sides, and a contact thickness. The reinforcing member has a reinforcement thickness, which is less than the contact thickness. The contact member is made from a first material having a first coefficient of thermal expansion, and the reinforcing member is made from a second different material having a second coefficient of thermal expansion. The first coefficient of thermal expansion is substantially the same as the second coefficient of thermal expansion.

The present invention includes a wear-resistant material including: a base material formed of pure aluminum or an aluminum alloy having a finely asperity structure on a surface thereof; and a coat including a hydrated oxide coat of aluminum, the coat being formed on the surface of the base material. Further, the present invention including a puffer cylinder including: a finely asperity structure on an inner-wall surface thereof; and a coat including a hydrated oxide coat of aluminum, the coat being formed on the inner-wall surface of the puffer cylinder. The present invention also includes a puffer-type gas circuit breaker includes the above puffer cylinder.

An electrode material wherein Cr-containing particles are finely miniaturized and uniformly dispersed while a Cu portion, which is highly conductive component, is also finely miniaturized and uniformly dispersed. The electrode material is prepared, for example, by: a mixing step (S1) for mixing a Cr powder and a heat resistant element powder; a provisional sintering step (S2) for provisionally sintering the mixed powder to obtain a solid solution of Cr and the heat resistant element; a pulverizing step (S3) for pulverizing the solid solution of Cr and the heat resistant element to obtain a solid solution powder of Cr and the heat resistant element; a molding step (S4) for molding the solid solution powder; a main sintering step (S5) for performing main sintering of the obtained molded body to obtain a sintered body (skeleton) of Cr and the heat resistant element; and a Cu infiltration step (S6) for infiltrating the sintered body of Cr and the heat resistant element with Cu.

A method for producing an electrode material, involving: (i) a step of preparing a powder of a solid solution of Cr and a heat resistant material selected from the group consisting of Mo, W, Ta, Nb, V and Zr, wherein either a peak corresponding to Cr element or a peak corresponding to the heat resistant element, which are observed by X ray diffraction measurement made on the powder of the solid solution, disappears; (ii) a step of molding the powder of the solid solution to obtain a molded body and then sintering the molded body to produce a sintered body; and (iii) a Cu infiltration step of infiltrating the sintered body with Cu.

A method for producing an electrode material, provided to involve: (i) a provisional sintering step of sintering a mixed powder containing a powder of a heat resistant element and a powder of Cr to obtain a solid solution where the heat resistant element and Cr are dissolved; (ii) a pulverizing step of pulverizing the solid solution to obtain a powder; (iii) a main sintering step of sintering a molded body obtained by molding the powder of the solid solution, to produce a sintered body; and (iv) a Cu infiltration step of infiltrating the sintered body with Cu.

According to one embodiment, a Vacuum interrupter includes a pair of electrodes provided such that their electrode opposed surfaces face each other, and an undulating structure provided in at least one of the electrode opposed surfaces. The undulating structure includes one or more projections which project from the electrode opposed surface, and depressions provided so as to be adjacent to the projections, respectively. The projections and the depressions are alternately provided in a direction crossing the electrode opposed surface. In a conducting state in which the electrodes are in contact with each other, the projections are in contact with the opposite electrode opposed surface.

Provided is a vacuum interrupter capable of improving an axial magnetic field intensity even at a contact portion other than a region of the contact portion corresponding to a region surrounded by an arm portion and a coil portion. In the vacuum interrupter according to the present disclosure, in each coil electrode, a bypass portion has: a second coil portion which extends so as to have an overlap with a corresponding first coil portion and a power feeding portion opposed to the first coil portion, in a circumferential direction; a first arm portion which connects the second coil portion and a ring portion; and a second arm portion which connects the second coil portion and the first coil portion.

A compact vacuum interrupter has an insulator element, a moving contact connection, a fixed contact connection, a moving contact, and a fixed contact. The moving contact has a moving contact rod and a moving-contact contact element. The fixed contact has a fixed contact rod and a fixed-contact contact element. The moving contact is formed with a material that is mechanically stronger than a material of the fixed contact.

A short-circuit current limiter has a vacuum switch in a main current path and a current-limiting unit connected in parallel therewith in a commutation current path. The vacuum switch has switching contacts. A material of contact pieces of the switching contacts is selected such that a mean value of the chopping current is at least 8 amperes.